目的 探讨二十二碳六烯酸（docosahexaenoic acid, DHA）联合中链甘油三酯（medium chain triglycerides, MCTs）对快速老化小鼠（senescence-accelerated mouse prone 8, SAMP8）神经元损伤的影响,并分析其可能的自噬-溶酶体通路机制。方法 将4月龄SAMP8小鼠随机分为4组：0.233% DHA添加组（DHA组）、10% MCTs添加组（MCTs组）、0.233% DHA+10% MCTs添加组（DHA+MCTs组）、对照组（Con-P组）;设置4月龄抗快速老化小鼠（senescence-accelerated mouse resistant 1, SAMR1）作为正常老化对照组（Con-R组）。饲料干预7个月后取小鼠脑组织并制备切片样本,通过Fluoro-Jade B（FJB）染色检测小鼠大脑皮层区神经元变性情况;采用尼氏染色检测神经元存活数量;使用免疫荧光检测自噬和溶酶体相关蛋白表达水平。结果 FJB染色结果显示,与Con-P组相比,DHA组、MCTs组、DHA+MCTs组变性神经元数量减少,且DHA+MCTs组变性神经元数量低于DHA组、MCTs组,差异均有统计学意义（P<0.05）;尼氏染色结果显示,DHA组、MCTs组、DHA+MCTs组神经元存活数量多于Con-P组,且DHA+MCTs组神经元存活数量高于DHA组、MCTs组,差异均有统计学意义（P<0.05）;免疫荧光结果表明,与Con-P组相比,DHA组、MCTs组、DHA+MCTs组mTOR表达水平升高,且DHA+MCTs组mTOR表达水平高于DHA组、MCTs组,而自噬及溶酶体功能的主要调节因子（TFEB）、自噬相关蛋白（LC3、Beclin-1）和溶酶体相关蛋白（LAMP1、LAMP2、CTSB、CTSD）的表达水平均降低,且DHA+MCTs组上述蛋白表达水平均低于DHA组、MCTs组,差异均有统计学意义（P<0.05）。结论 DHA联合MCTs可减轻SAMP8小鼠大脑皮层区神经元损伤,且DHA和MCTs联合补充的效果优于单独补充,其作用机制可能与调控mTOR/TFEB介导的自噬-溶酶体通路有关。
Abstract
Objective To investigate the effects of docosahexaenoic acid (DHA) combined with medium chain triglycerides (MCTs) on neuronal damage in senescence-accelerated mouse prone 8 (SAMP8) mice and the potential autophagy-lysosomal pathway mechanism. Methods 4-month-old SAMP8 mice were randomly assigned to four groups: 0.233% DHA supplementation (DHA group), 10% MCTs supplementation (MCTs group), 0.233% DHA+10% MCTs supplementation (DHA+MCTs group), and control (Con-P group). Four-month-old senescence-accelerated mouse resistant 1 (SAMR1) mice served as the normal aging control group (Con-R group). After 7 months of dietary intervention, brain tissue sections were prepared. Fluoro-Jade B (FJB) staining was used to assess neuronal degeneration in the cerebral cortex. Nissl staining was conducted to quantify surviving neurons. Immunofluorescence was employed to assess expression levels of autophagy-related and lysosome-related proteins. Results FJB staining revealed that compared to the Con-P group, the DHA, MCTs, and DHA+MCTs groups exhibited reduced numbers of degenerated neurons, while the DHA+MCTs group demonstrated the lowest number of degenerated neurons compared to the DHA and MCTs groups, and these differences were all statistically significant (P<0.05). Nissl staining revealed that the number of surviving neurons in the DHA, MCTs, and DHA+MCTs groups was higher than in the Con-P group. The DHA+MCTs group exhibited the highest number of surviving neurons (P<0.05). Immunofluorescence results showed that compared to the Con-P group, mTOR expression levels were higher in the DHA, MCTs, and DHA+MCTs groups (P<0.05). Furthermore, mTOR expression in the DHA+MCTs group was higher than in the DHA and MCTs groups. Meanwhile, expression levels of the key regulatory proteins for autophagy and lysosomal function (TFEB), the autophagy-related proteins (LC3 and Beclin-1) and the lysosomal-associated proteins (LAMP1, LAMP2, CTSB and CTSD) were all significantly reduced (P<0.05). Conclusion DHA combined with MCTs alleviates neuronal damage in the cerebral cortex of SAMP8 mice and the combined supplementation yields superior effects compared to either DHA or MCTs alone. The mechanism is related to the regulation of the mTOR/TFEB-mediated autophagy-lysosomal pathway.
关键词
二十二碳六烯酸 /
中链甘油三酯 /
自噬-溶酶体通路 /
神经元 /
SAMP8小鼠
Key words
docosahexaenoic acid /
medium chain triglycerides /
autophagy-lysosomal pathway /
neuron /
SAMP8 mice
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参考文献
[1] Donovan LJ, Brewer CL, Bond SF, et al. Aging and injury drive neuronal senescence in the dorsal root ganglia[J]. Nat Neurosci, 2025, 28: 985–997.
[2] Tabibzadeh S.Role of autophagy in aging: the good, the bad, and the ugly[J]. Aging Cell, 2023, 22: e13753.
[3] Miceli C, Leri M, Stefani M, et al. Autophagy-related proteins: potential diagnostic and prognostic biomarkers of aging-related diseases[J]. Ageing Res Rev, 2023, 89: 101967.
[4] Chae CW, Yoon JH, Lim JR, et al. TRIM16-mediated lysophagy suppresses high-glucose-accumulated neuronal Aβ[J]. Autophagy, 2023, 19: 2752–2768.
[5] Díaz M, Mesa-Herrera F, Marín R.DHA and its elaborated modulation of antioxidant defenses of the brain: implications in aging and AD neurodegeneration[J]. Antioxidants, 2021, 10: 907.
[6] Power R, Nolan JM, Prado-Cabrero A, et al. Omega-3 fatty acid, carotenoid and vitamin E supplementation improves working memory in older adults: a randomised clinical trial[J]. Clin Nutr, 2022, 41: 405–414.
[7] 宫铭. DHA抑制线粒体过度自噬减轻Aβ对周细胞的毒性作用研究[D]. 广州:南方医科大学, 2024.
[8] Nakamura K, Hagihara K, Nagai N, et al. Ketogenic effects of medium chain triglycerides containing formula and its correlation to breath acetone in healthy volunteers: a randomized, double-blinded, placebo-controlled, single dose-response study[J]. Front Nutr, 2023, 10: 1224740.
[9] Fortier M, Castellano CA, St-Pierre V, et al. A ketogenic drink improves cognition in mild cognitive impairment: results of a 6-month RCT[J]. Alzheimers Dement, 2021, 17: 543–552.
[10] Camberos-Luna L, Gerónimo-Olvera C, Montiel T, et al. The ketone body, β-hydroxybutyrate stimulates the autophagic flux and prevents neuronal death induced by glucose deprivation in cortical cultured neurons[J]. Neurochem Res, 2016, 41: 600–609.
[11] Thau-Zuchman O, Svendsen L, Dyall SC, et al. A new ketogenic formulation improves functional outcome and reduces tissue loss following traumatic brain injury in adult mice[J]. Theranostics, 2021, 11: 346–360.
[12] 中国营养学会.《中国居民膳食营养素参考摄入量》2023修订版简介[J]. 营养学报, 2023, 45: 521–524.
[13] Duan H, Yang T, Li C, et al. Supplementation of medium-chain triglycerides combined with docosahexaenoic acid improves cognitive function in Chinese older adults with mild cognitive impairment: a randomized double-blind, placebo-controlled trial[J]. J Affect Disord, 2025, 378: 263–270.
[14] Hosono T, Mouri A, Nishitsuji K, et al. Arachidonic or docosahexaenoic acid diet prevents memory impairment in Tg2576 mice[J]. J Alzheimers Dis, 2015, 48: 149–162.
[15] Wang Z, Zhang D, Cheng C, et al. Supplementation of medium-chain triglycerides combined with docosahexaenoic acid inhibits amyloid beta protein deposition by improving brain glucose metabolism in APP/PS1 mice[J]. Nutrients, 2023, 15: 4244.
[16] Juby AG, Blackburn TE, Mager DR.Use of medium chain triglyceride (MCT) oil in subjects with Alzheimer’s disease: a randomized, double-blind, placebo-controlled, crossover study, with an open-label extension[J]. Alzheimers Dement, 2022, 8: e12259.
[17] Rhea EM, Banks WA.The SAMP8 mouse for investigating memory and the role of insulin in the brain[J]. Exp Gerontol, 2017, 94: 64–68.
[18] Ong J, Sasaki K, Ferdousi F, et al. Senescence accelerated mouse-prone 8: a model of neuroinflammation and aging with features of sporadic Alzheimer’s disease[J]. Stem Cells, 2025, 43: sxae091.
[19] Conti F, McCue JJ, DiTuro P, et al. Mitigating traumatic brain injury: a narrative review of supplementation and dietary protocols[J]. Nutrients, 2024, 16: 2430.
[20] 付朝旭, 许妍姬. 鱼油联合锌硒对衰老模型小鼠学习记忆障碍及淀粉样前体蛋白酶解通路的保护作用[J]. 营养学报, 2020, 42: 56–60.
[21] Cunnane SC, Trushina E, Morland C, et al. Brain energy rescue: an emerging therapeutic concept for neurodegenerative disorders of ageing[J]. Nat Rev Drug Discov, 2020, 19: 609–633.
[22] Sun Y, Zhou D, Wang Y, et al. Medium-chain triglycerides combined with DHA improve cognitive function by inhibiting neurocyte apoptosis of the brain in SAMP8 mice[J]. Exp Gerontol, 2024, 194: 112520.
[23] Parzych KR, Klionsky DJ.An overview of autophagy: morphology, mechanism, and regulation[J]. Antioxid Redox Signal, 2014, 20: 460–473.
[24] Bar-Yosef T, Damri O, Agam G.Dual role of autophagy in diseases of the central nervous system[J]. Front Cell Neurosci, 2019, 13: 196.
[25] Bazan NG, Molina MF, Gordon WC.Docosahexaenoic acid signalolipidomics in nutrition: significance in aging, neuroinflammation, macular degeneration, Alzheimer’s, and other neurodegenerative diseases[J]. Annu Rev Nutr, 2011, 31: 321–351.
[26] Tatsumi Y, Kato A, Niimi N, et al. Docosahexaenoic acid suppresses oxidative stress-induced autophagy and cell death via the AMPK-dependent signaling pathway in immortalized Fischer rat Schwann cells 1[J]. Int J Mol Sci, 2022, 23: 4405.
[27] Li G, Li Y, Xiao B, et al. Antioxidant activity of docosahexaenoic acid (DHA) and its regulatory roles in mitochondria[J]. J Agric Food Chem, 2021, 69: 1647–1655.
[28] M'Bra PEH, Hamilton LK, Moquin-Beaudry G, et al. Medium-chain triglycerides improve cognition and systemic metabolism in mouse models of Alzheimer's disease[J]. Brain, 2026, 149: 105-122.
[29] Makki K, Taront S, Molendi-Coste O, et al. Beneficial metabolic effects of rapamycin are associated with enhanced regulatory cells in diet-induced obese mice[J]. PLOS One, 2014, 9: e92684.
[30] Yang CB, Liu J, Tong BCK, et al. TFEB, a master regulator of autophagy and biogenesis, unexpectedly promotes apoptosis in response to the cyclopentenone prostaglandin 15d-PGJ2[J]. Acta Pharmacol Sin, 2022, 43: 1251–1263.
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