Objective: To investigate the effects of PM_2.5 exposure at different stages of early life on the prefrontal cortex of offspring rats. Methods: Twelve pregnant SD rats were randomly divided into four groups: Control group (CG), Maternal pregnancy exposure group (MG), Early postnatal exposure group (EP) and Perinatal period exposure group (PP), 3 rats in each group. The pregnant and offspring rats were exposed to clean air or 8-fold concentrated PM_2.5. MG was exposed from gestational day (GD) 1 to GD21. EP was exposed from postnatal day (PND) 1 to PND21, and PP was exposed from GD1 to PND21. After exposure, the prefrontal cortex of 6 offspring rats in each group was analyzed. HE staining was used to observe the pathological damage in the prefrontal cortex. ELISA was employed to detect neuroinflammatory factors, and HPLC/MSC was applied to determine neurotransmitter content. Western blot and colorimetry were applied for detecting astrocyte markers and oxidative stress markers, respectively. Results: Compared with MG and CG, the pathological changes of prefrontal cortex in PP and EP were more obvious. Compared with MG and CG, the neuroinflammatory factors (IL-1, IL-6, TNF-α) in PP and EP were increased significantly (P＜0.01), the level of MT were decreased significantly (P＜0.05), and the level of oxytocin (OT) showed a downward trend; the level of neurotransmitter ACh was also increased significantly (P＜0.01). Compared with MG and CG, the GFAP level of PP and EP showed an upward trend, the level of oxidative stress index SOD in PP and EP was decreased significantly (P＜0.01), and the level of ROS was increased significantly (P＜0.01). Compared with the offspring rats of CG and MG, the CAT level of PP was decreased significantly (P＜0.01, P＜0.05). Compared with the offspring rats of CG, the CAT level of EP was decreased significantly (P＜0.05). There was no significant difference in IL-1, IL-6, TNF-α, MT, OT, ACh, GFAP, SOD, ROS and CAT levels between PP and EP, or MG and CG. Conclusion: PM_2.5 exposure in early life has adverse effects on the prefrontal cortex of offspring male rats, and early birth exposure may be more sensitive.

Objective: To investigate the effects of the pyrin domain-containing protein 3 (NLRP3) inflammasome inhibitor MCC950 on nerve injury in rats with intracerebral hemorrhage(ICH). Methods: Seventy-two SD rats were randomly divided into three groups (n=24): Sham group, ICH group and MCC950 group. ICH group and MCC950 group rats were injected with autogenous non-anticoagulant blood to establish ICH model, and then the rats in MCC950 group were intraperitoneally injected with MCC950 at the dose of 10 mg/kg(2 mg/ml) for 3 days after ICH model was established. Seventy-two hours after the establishment of the model, the forelimb placement test, the corner test and mNSS score were performed to observe the neurological function of the rats with ICH. The volume of hematoma was observed in fresh brain tissue sections. HE staining was used to observe the pathological changes of brain tissue. The dry-wet weight ratio was calculated to evaluate the changes of brain tissue edema. The degeneration of neurons was observed by FJC staining. The neuronal apoptosis was observed by TUNEL staining. The protein expression and activation levels of NLRP3, ASC, caspase-1, IL-1β, IL-18 and GSDMD were determined by Western blot. Results: Compared with sham group, the percentage of successful placement of left forelimb and left turn was decreased significantly (P＜0.01, P＜0.05), mNSS score was increased significantly (P＜0.01) in ICH group. Hematoma volume was increased significantly, the number of microglial cells around the hematoma was increased, the number of neurons was decreased, nerve cell swelled, some cells showed pyknotic necrosis, and the staining was deepened. The water content of the right base was increased significantly (P＜0.05). The number of FJC positive and TUNEL positive cells around the hematoma was increased significantly (P＜0.05). The levels of NLRP3, ASC, caspase-1, pro-caspase-1, caspase-1/pro-caspase-1 ratio, GSDMD-N, GSDMD, GSDMD-N/GSDMD ratio, IL-1β and IL-18 were increased significantly (P＜0.01, P＜ 0.05). Compared with ICH group, the percentage of successful placement of left forelimb and left turn was increased significantly in MCC950 group (P＜0.05), while the mNSS score and the volume of hematoma were decreased significantly (P＜0.01), the swelling degree of nerve cells around the hematoma was reduced significantly, and the number of pyrotic necrotic cells was decreased. The water content of the right base was decreased significantly (P＜0.05), and the number of FJC positive and TUNEL positive cells around the hematoma was decreased significantly (P＜0.05). The levels of NLRP3, ASC, caspase-1, pro-caspase-1, caspase-1/pro-caspase-1 ratio, GSDMD-N, GSDMD, GSDMD-N/GSDMD ratio, IL-1β and IL-18 were decreased significantly (P＜0.05). Conclusion: MCC950 can ameliorate nerve injury after ICH by inhibiting NLRP3 inflammasome mediated inflammation and pyroptosis.

Objective: To uncover the time-dependent expression pattern of ptk2b gene and ptk2b-encoded protein, protein tyrosine kinase 2 beta(PTK2B), in the brain tissues of transgenic animal models of Alzheimer’s disease (AD) and its relationship with the levels of Aβ_1-42, phosphorylation of Tau (p-Tau) and low density lipoprotein receptor-related protein-1(LRP-1) in blood and brain tissues. Methods: In this study, 5-, 10- and 15-month-old APPswe/PS1dE9 double-transgenic mice harboring the genotype of AD confirmed by the gene test were divided into the 5-, 10- and 15-month-old experiment groups, and simultaneously, age-matched C57BL/6J mice were placed into the corresponding control groups, with 8 mice in each group. All mice were subjected to the Morris Water Maze for test of cognitive and behavioral ability. Expression profiles of PTK2B, Aβ_1-42, p-Tau/Tau and LRP-1 in the hippocampus or blood of mice were quantified by using the immunohistochemistry staining, Western blot or enzyme-linked immunosorbent assay (ELISA), while the mRNA expression of ptk2b in the hippocampus was quantified by using the real-time quantitative polymerase chain reaction (qRT-PCR). Results: Results of experiment groups demonstrated that as mice aged, the expression levels of PTK2B, ptk2b mRNA, Aβ_1-42 and p-Tau/Tau in the hippocampus were increased, and the expression of LRP-1 was decreased gradually. While in the blood, the level of Aβ_1-42 was decreased, and the cognitive and behavioral ability was decreased in an age-dependent manner (all P＜ 0.05). However, comparisons among the control groups, only the age-dependent downregulation of LRP-1 were observed in hippocampus(P＜0.05), but other indicators had no significant differences (P＞0.05). Conclusion: In the hippocampus of APP/PS1 double-transgenic mice, the expressions of PTK2B, Aβ_1-42 and p-Tau/Tau are upregulated, LRP-1 is downregulated, while cognitive and behavioral ability is decreased, and such changes are presented in a time-dependent manner.

Objective: To investigate the effects of Zhongfeng capsule on the autophagy-related proteins expression in rats with cerebral ischemia/reperfusion injury (CI/ RI), and to explore its neural protection mechanisms of the decoction. Methods: Rat middle cerebral artery ischemia/reperfusion injury model (ischemia for 2 h, reperfusion for 24 h) was prepared by the improved line plug method. Sixty male SD rats were randomly divided into sham operation group, model group, butylphthalide group(0.054 g/kg), Zhongfeng capsule high-dose groups (1.08 g/kg), Zhongfeng capsule middle-dose groups (0.54 g/kg), Zhongfeng capsule low-dose groups (0.27 g/kg), with 10 rats in each group. Rats were treated with Zhongfeng capsule by gavage once a day for 10 days. The rats were sacrificed and the brain tissue was obtained after the experiment in each group. Score neurological deficit was evaluated after 24 h of the last intervention in rat of each group. The pathological changes of brain tissue were observed by HE staining. The serum levels of estradiol (E2) and follicle stimulating hormone (FSH) were determined by ELISA. The expressions of key genes and proteins of PI3K/Akt/Beclin1 signaling pathway in brain tissue were detected by qRT-PCR and Western blot respectively. Results: Compared with the sham operation group, the body weight and protein expressions of p-PI3k and p-Akt in brain tissue of rats were decreased significantly in the model group, while the brain index, neurological deficit score, gene and protein expressions of Beclin1 and LC3 were increased markedly in the model group(P＜0.05 or P＜0.01). In the model group, nerve cells of brain tissue were loosely packed, interstitial edema, triangular in shape, nuclear pyknosis and dark-blue staining were observed. Compared with the model group, the body weight of rats was increased obviously, the neurological deficit score was decreased significantly and the pathological injury of brain tissue was alleviated evidently in high-dose of Zhongfeng capsule group (P＜0.05). The brain index, the gene and protein expressions of Beclin1 and LC3 were decreased apparently in Zhongfeng capsule treatment groups(P＜0.05 or P＜0.01), while the expressions of p-PI3k and p-Akt in brain tissue were increased evidently in Zhongfeng capsule treatment groups(P＜0.05 or P＜0.01). Conclusion: Zhongfeng capsule can inhibit autophagy and improve brain neurons lesion of CIRI rats, the mechanism may be related to regulate the expression of Beclin1 and LC3 in PI3K/Akt/Beclin1 signaling pathway.

Objective: To investigate the effects of glycogen synthase kinase-3β (GSK3β)/eukaryotic extension factor kinase 2 (eEF2K) signaling pathway on the process of pulmonary fibrosis through in vivo experiments, and find new ideas for clinical treatment of pulmonary fibrosis. Methods: The pulmonary fibrosis model of C57BL/6 male mice was induced by bleomycin with intratracheal injection at the dose of 2 mg/kg. After 14 days of modeling, animals were divided into model group, negative inhibition group and inhibition group (n=5 for each group), and control group was not processed. The inhibition group was treated with TDZD-8 (4 mg/kg) after modeling, the negative inhibition group was given DMSO solution after modeling, and the samples were collected after 28 days. Hematoxylin-eosin staining method was used to detect lung fibrosis in mice and scored according to Ashcroft scale. Expression levels of GSK3β, p-GSK3β, eEF2K, p-eEF2K (Ser70, Ser392, Ser470), precursor protein of matrix metalloproteinase-2 (pro-MMP-2), matrix metalloproteinase-2 (MMP-2), collagen I (Col I), collagen Ⅲ (Col Ⅲ) and α-smooth muscle actin (α-SMA) were detected by Western blot. Results: Compared with control group, the fibrosis score was up-regulated, the expression levels of GSK3β, p-GSK3β, p-eEF2K (Ser70, Ser392, Ser470), pro-MMP-2, MMP-2, Col I, Col Ⅲ and α-SMA were increased, while that of eEF2K was decreased in model group (P＜0.05). Compared with model group, the fibrosis score, expression levels of GSK3β, p-GSK3β, p-eEF2K (Ser70, Ser392, Ser470), pro-MMP-2, MMP-2, Col I, Col Ⅲ and α-SMA were decreased, but the expression level of eEF2K was increased in inhibition group (P＜0.05). Conclusion: GSK3β can activate eEF2K by phosphorylation at the sites of Ser70, Ser392 and Ser470, increase the contents of fibrosis indicators, promote the formation of pulmonary fibrosis, and aggravate lung tissue lesions.

Objective: To investigate the repair effect and JNK/NF-κB,SOX9 mechanisms of vibration exercise with different frequencies on articular cartilage in rats with early knee osteoarthritis. Methods: Forty-eight adult male SD rats were randomly divided into six groups(n=8):model control group(MC),high frequency vibration group 1 (GP₁,60 Hz),high frequency vibration 2 group (GP₂,40 Hz),medium frequency vibration group (ZP,20 Hz),minor frequency group(DP,10 Hz)and normal control group(NC). Except for NC group,the rats in each group were made into early knee osteoarthritis model after six weeks of knee joint cavity injection of papain solution and 2% mixture l-cysteine on the 1^st,4 ^th and 7^th day. Each exercise group was subjected vibration to 40 minutes a day with amplitude of 2～5 mm and 5 days a week. Four weeks later, the articular cartilage of the lateral femoral condyle of the both back leg knee joints were detected by HE staining,serine O staining and Mankin scores for morphological observation. The expression levels of JNK,NF-κB p65 and Sox9 mRNA in articular cartilage of the medial femoral condyle were detected by RT-qPCR,and the protein expressions of JNK,NF-κB p65 and Sox9 were detected by Western blot. Results: Compared with the NC group,the Mankin score in other groups was significantly higher (P＜0.01). Compared with the MC group,the Mankin score of each vibration group was significantly lower(P＜0.05),the mRNA and protein expressions of JNK and NF-κB p65 in each vibration training group were significantly lower (P＜0.01),the expressions of Sox9 mRNA and protein in vibration training group were increased significantly (P＜0.01). Compared with the higher frequency group,the Mankin score,the mRNA and protein expressions of JNK and NF-κB p65 of lower frequency group were significantly lower (P＜0.05 or P＜0.01). But the expressions of Sox9 mRNA and protein were significantly higher (P＜ 0.05 or P＜0.01). Conclusion: Vibration exercise of different frequencies may present varying degrees of cartilage repair impact in rats with early knee osteoarthritis,and the cartilage repair by low-frequency vibration training is better than that by high-frequency vibration. This can be one of the mechanisms on controlling collagen synthesis by down-regulating JNK/NF-κB expression and increasing SOX9 activity of OA articular cartilage.

Objective: To investigate the effects of continuous exercise training (CT) and high-intensity interval exercise training (HIIT) on liver lipid metabolism and the correlation of the level of fibroblast growth factor 21(FGF21) in serum and liver tissues. Methods: Male SD rats were randomly divided into normal diet group (N) and obesity model group (H) after 1 week of adaptive feeding. Rats in the obesity model group were fed with 45% high-fat diet for about 8 weeks, and 20% weight increase compared with normal rats was considered as obesity. The rats were divided into normal diet control group (LC), normal diet HIIT group (LHI), normal diet CT group (LCT), High fat diet-induced obese control group (OC), obese HIIT group (OHI), and obese CT group (OCT) (n=10). Exercised rats were given weight-bearing swimming training intervention for 8 weeks. Blood samples were collected at least 24h after the last exercise intervention to detect the serum levels of inflammatory factors and FGF21. Liver tissue samples were collected to detect the lipid content, lipid metabolic enzyme content and FGF21 expression level. Results: Compared with LC group, the body weight, serum inflammatory factors levels and hepatic triglyceride content were increased significantly (P＜0.05). Hepatic triglyceride content was downregulated in LHI group and FGF21 expression level was enhanced in LCT group (P＜0.05). Compared with OC group, the body weight and hepatic triglyceride content were decreased significantly (P＜0.05), mitochondrial CPT-1β and β-HAD enzyme contents in liver were increased significantly (P＜0.05) in OHI group, the contents of LPL and FAT/CD36 enzyme in liver and the levels of FGF21 in serum and liver of OCT group were increased significantly (P＜0.05). Conclusion: Both exercise modes can reduce the body weight in normal and obese rats, and lipid deposition in the liver of obese rats. HIIT has a more significant effect on alleviating liver lipid deposition in obese rats by upregulating mitochondrial lipid oxidation level in normal and obese rats. CT improves the levels of FGF21 in serum and liver tissues of normal and obese rats, enhances enzyme contents that involved in fatty acids uptake to the liver, which has limited effect on alleviating lipid deposition in liver of obese rats.

Objective: To investigate the effects of long-chain noncoding RNA Linc00673 overexpression on proliferation and apoptosis of gastric cancer cells and its mechanisms. Methods: The recombinant lentivirus expressing plasmid pLVX-Linc00673 and the control empty plasmid pLVX-NC were packaged and amplified in 293T cells, and the recombinant lentivirus was transfected into gastric cancer cell line MGC-803 to establish a cell line stably overexpressing Linc00673. The expression of Linc00673 gene was detected by real-time fluorescence quantitative PCR. The growth and proliferation of cells were observed by MTT assay and clone formation assay. Cell cycle and apoptosis were detected by flow cytometry. The expressions of cell cycle related regulatory genes were detected by qPCR. The expressions of key molecules in the PI3K/Akt signaling pathway and tumor proliferation related proteins were detected by Western blot. Results: The expressions of Linc00673 in gastric cancer cell line MGC-803, BGC-823 and AGS were significantly higher than that in normal gastric mucosa cell line GES-1 (P＜0.05). MGC-803 cell line with stable overexpression of LINC00673 was established, and the expression level of LincC00673 was 200 times higher than that of the control empty carrier group. Overexpression of Linc00673 promoted proliferation of MGC-803 cells (P＜0.05) and clone formation (P＜0.05), inhibited cell apoptosis and affected the G1→S phase progression of cell cycle (P＜0.01). Overexpression of Linc00673 could affect the expressions of cell cycle regulatory gene CCNG2, P19 and CDK1 in MGC-803. Western blot showed that Linc00673 overexpression not only promoted the expressions of the key molecule pAkt in PI3K / Akt signaling pathway and its downstream target NF-κ B and Bcl-2 protein, but also up regulated the expressions of tumor related factors β-catenin and EZH2 proteins. Conclusion: Overexpression of Linc00673 may promote proliferation and inhibit apoptosis of MGC-803 cells through PI3K/Akt signaling pathway.

Objective: To investigate the effect of Xuanfu Daizhe decoction on the stemness of esophageal cancer cells. Methods: The BALB/c nude mice were randomly divided into the control group and experimental group, 5 mice in each group, which were continuously administered with normal saline and Xuanfu Daizhe decoction (9.89 g/kg) by gastrogavage, respectively. Human esophageal carcinoma cells ECA-109 (5×10⁶) were subcutaneously injected into the mice on the 8th day. Tumor volume was measured twice a week. The mice were sacrificed 4 weeks after injection, and the tumor tissue and mouse serum were collected. The expressions of the major stemness-regulating transcription factors, i.e., NANOG, OCT4 and SOX2, were detected by RT-qPCR, Western Blot and immunohistochemistry. ECA-109 cells were treated with 10% fetal bovine serum and serum from the above two groups of mice for 48 hours respectively, and three replicate wells were set in each group, and the expressions of NANOG, OCT4, SOX2 and the levels of AKT and p-AKT were detected by RT-qPCR and Western Blot, respectively. ALDH activity in tumor cells was detected by flow cytometry; the number of spheroids of tumor cells was detected by the spheroidization experiment. Results: Compared with the control group, the growth and size of esophageal cancer tumors were significantly inhibited by Xuanfu Daizhe Decoction; the expressions of NANOG, OCT4, SOX2, the ALDH activity, the number of spheroids, and the levels of AKT and phosphorylated AKT (p-AKT) in esophageal cancer cells were significantly reduced by Xuanfu Daizhe Decoction both in vivo and in vitro. Conclusion: Xuanfu Daizhe Decoction inhibits the stemness of esophageal cancer cells, it may be a potentially effective drug for the treatment of esophageal cancer and provides a theoretical basis for the exploration of new effective drugs for the treatment of esophageal cancer.

Objective: To investigate the mechanism that hypoxia promotes the migration of lung adenocarcinoma A549 cells. Methods: A549 cells were cultured and cells that knockdown of acetyl-CoA carboxylase 1 (ACC1) were obtained by transfection with lentivirus, and cells that knockdown of sterol regulatory element-binding proteins-1 (SREBP-1) were obtained by treated with si-RNA. A549 cells were treated with hypoxia combined with hypoxia inducible factor-1α (HIF-1α) inhibitor PX-478 (25 μmol); Hypoxia combined with linoleic acid (LA) (20 μmol) treated A549 cells with ACC1 knockdown, and A549 cells with SREBP-1 knockdown were treated by hypoxia. Transwell migration assay was used to detect cell migration. Western blot was conducted to detect HIF-1α, ACC1 and epithelial mesenchymal transition (EMT) related proteins, Vimentin, E-Cadherin and SREBP-1; Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) was performed to detect the changes of ACC1 and SREBP-1 mRNA in A549 cells after hypoxia and HIF-1α inhibitor PX-478 (25 μmol) treatment. Each experiment was repeated three times. Results: Compared with the normoxic control group, hypoxia promoted the migration of A549 cells (P＜0.01), and up-regulated the expressions of ACC1, HIF-1α (all P＜0.01) and SREBP-1 (P＜0.05). PX-478 (25 μmol) inhibited the migration of A549 cells induced by hypoxia and down-regulated the expression of SREBP-1 (all P＜0.05). ACC1 mRNA and SREBP-1 mRNA levels were increased after hypoxia treatment of A549 cells (all P＜0.05). The levels of ACC1 mRNA and SREBP-1 mRNA were decreased after A549 cells treated with hypoxia combined with PX-478 (25 μmol) for 24 h (P＜0.05, P＜0.01). Knockdown of SREBP-1 in A549 cells was obtained by transfection with si-RNA. Transwell migration assay showed the number of cell migration in si-SREBP-1 group was less than that in normoxia control group (P＜0.01). The si-SREBP-1 group and the si-NC group were treated with hypoxia. Compared with the control group, the number of cell migration in the si-SREBP-1 group was decreased (P＜0.01), however, the difference was not statistically significant compared with the normoxia si-SREBP-1 group (P＞0.05). Western blot showed that the expression of ACC1 in the si-SREBP-1 group was lower than that in the control group (P＜0.01). Compared with the control group, the expression of ACC1 was decreased after si-SREBP-1 group treated with hypoxia (P＜0.01). Knockdown of ACC1 inhibited the migration of A549 cells (P＜0.05). After knockdown of ACC1, the migration number of A549 cells under normoxia and 5% O₂ conditions had no significant difference (P＞0.05). Application of LA under hypoxia condition rescued ACC1-knockdown induced inhibitory effect on hypoxia-promoted A549 cell migration (P＜0.05). Conclusion: Hypoxia promotes migration of lung adenocarcinoma A549 cells by regulating fatty acid metabolism through HIF-1α/SREBP-1/ACC1 pathway.

Objective: To establish a detection method based on Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) that can sensitively detect the second messenger cyclic AMP (cAMP) in the cytoplasm. Methods: The eukaryotic expression vectors of CFTR and YFP-H148Q / I152L were constructed respectively. FRT cells co-expressing CFTR and YFP-H148Q / I152L were obtained by liposome transfection. The expression of CFTR and YFP-H148Q / I152L in FRT cells was observed by an inverted fluorescence microscopy, and flow cytometry was used to detect the purity of cells; The cell model was identified by the fluorescence quenching kinetics test. The validation of the cell model which could screen CFTR modulators was verified by the fluorescence quenching kinetics experiments. The radioimmunoassay was used to detect the cAMP concentration in cytoplasm after adding CFTR activator. Results: The results of the inverted fluorescence microscope showed that CFTR was expressed in the cell membrane and YFP-H148Q / I152L was expressed in the cytoplasm of FRT cells. The FRT cell model stably co-expressing ANO1 and YFP-H148Q / I152L was successfully constructed. The model could screen CFTR modulators, and the slope of fluorescence change and the concentration of CFTR modulators were in a dose-dependent manner. The slope of the fluorescence could reflect the cAMP concentration in the cytoplasm. The cell model could sensitively detect the intracellular cAMP concentration. Conclusion: The cell model could efficiently and sensitively detect the second messenger cAMP concentration in the cytoplasm, and it provided a simple and efficient method for the study of other targets associated cAMP signal.

Objective: To compare the difference between the built-in and external reference electrode of microwire electrode array in the process of recording rat brain neuron firings, optimizing the production and embedding of the microwire electrode array, and providing a more affordable and excellent media tool for multi-channel electrophysiological real-time recording system. Methods: A 16 channel microwire electrode array was made by using nickel chromium alloy wires, circuit board, electrode pin and ground wires (silver wires). The reference electrode of the microwire electrode array was built-in (the reference electrode and electrode array were arranged in parallel) or external (the reference electrode and ground wire were welded at both ends of one side of the electrode), and the difference between the two electrodes was observed and compared in recording neuronal discharges in ACC brain area of rats. Experimental rats were divided into built-in group and external group, n=8-9. The test indicators included signal-to-noise ratio (n=8), discharge amplitude (n=380) and discharge frequency (n=54). Results: The microwire electrode array with both built-in and external reference electrodes successfully recorded the electrical signals of neurons in the ACC brain region of rats. Compared with the external group, the electrical signals of neurons in built-in group had the advantages of a higher signal-to-noise ratio (P＜0.05), a smaller amplitude of background signals and less noise interference, and a larger discharge amplitude(P＜0.05); there was no significant difference in spike discharge frequency recorded by these two types of electrodes (P＞0.05). Conclusion: When recording the electrical activity of neurons in the ACC brain region of rats, the microwire electrode array with built-in reference electrode recorded electrical signals with higher signal-to-noise ratio and larger discharge amplitude, providing a more reliable tool for multi-channel electrophysiology technology.

Objective: To establish an improved method of separating microglia from aged rats and to observe the biological characteristics of spinal microglia of aged rats. Methods: Young SD rats (2 months) were used as control group. Single cell suspension of rat microglia were prepared by trypsin, trypsin substitutes or mechanical net rubbing method. Then, by assessing the purity and survival rate of cells, and observing the morphological characteristics and analyzing the inflammatory functional characteristics, we optimized the isolation and purification method of microglia from aged rats (20 months old) , and observed the functional characteristics of spinal microglia in aged rats. Results: The survival rate of cells digested by pancreatic enzyme was low(young rats 83%, aged rats 60%). Although the survival rate of mechanical net rubbing method was higher than that of pancreatic enzyme digest methods (95%), the cell acquisition rate was lower(young rats(0.207±0.020)×10⁶, aged rats(0.243±0.023)×10⁶). Trypsin substitute dissociation combining density gradient centrifugation method was the best way to get abundant, active and higher survival microglia, and the purity reached more than 85%. We used this method to separate microglia from spinal cord of rats. Compared with the young rats, the spinal cord tissue of old rats was larger, the digestive fluid volume was higher, but the digestion time was shorter. Compared with the young rats, the aged rat spinal microglia had larger and rounder cell body, fewer and shorter protrusions, it tended to be activated morphologically, the level of proinflammatory cytokine IL-1β of microglia in aged rats was lower, and the level of antiinflammatory factor IL-10 was higher. Conclusion: The method of trypsin substitute dissociation combined with density gradient centrifugation was successfully established to isolate and purify microglia from spinal cord of rats, the spinal microglia of old rats showed anti-inflammatory phenotype.