Abstract: Objective: To investigate the molecular protective mechanisms of Huangqi decoction inhibiting the apoptosis of renal cells in the ¹²C⁶⁺ radiation brain model rats. Methods: Fifty Wistar rats were randomly divided into five groups: normal control group, radiation alone model group, Huangqi decoction (high-dose, middle-dose and low-dose ) groups. The normal control group and the radiation alone group were treated with saline10 ml/(kg·d) by gavage, the Huangqi decoction treatment groups were treated with Huangqi decoction at the doses of 4.5, 9 and 18 g/(kg·d) by gavage respectively. After 7 d, except mice in normal control group, the brain of the rats in radiation alone model group, high-dose, middle-dose and low-dose Huangqi decoction group were radiated by 4 Gy ¹²C⁶⁺ ion once. The rats were killed by the femoral artery after irradiation 7 d. The pathomorphism changes of renal tissue were observed by HE, the IL-6 level in serum was detected by ELISA, the gene expressions of Bcl-2, Bax and caspase-3 in renal tissue were assessed by RT-PCR, and the protein expressions of Bcl-2, Bax, caspase-3 and NF-κB in renal tissue were analyzed by immunehistochemical staining. Results: Compared with normal control group, the body weight and kidney index were decreased significantly, the expression of Bcl-2 in renal tissue was decreased significantly, the serum content of IL-6 was increased obviously, and the expressions of Bax, caspase-3 and NF-κB in renal tissue were increased significantly in the radiation alone model group (P＜0.01). The mesangial cells proliferated obviously, interstitial vessels of renal tubules were dilated and congested obviously, the lumen of renal tubules was narrow and irregular in the radiation alone model group. As compared with the radiation alone model group, the body weight and the kidney index were increased obviously in high-dose Huangqi decoction group, the gene and protein expressions of Bcl-2 in renal tissue were increased significantly in Huangqi decoction intervention group(P＜0.05 or P＜0.01). whereas, the protein expressions of Bax and caspase-3 in renal tissue were decreased significantly in middle-dose and high-dose Huangqi decoction group, the serum content of IL-6 was decreased obviously, the gene expressions of Bax and caspase-3 in renal tissue were decreased significantly and the protein expression of NF-κB in renal tissue was decreased significantly in Huangqi decoction intervention group(P＜0.05 or P＜0.01). The proliferation of mesangial cells was improved and the contour of renal tubules was clear in high-dose huangqi decoction group. Conclusion: High-dose of huangqi decoction has protective effect on kidney in rats induced by ¹²C⁶⁺ radiation brain, the mechanism may be related to the regulation of Bcl-2/NF-κB signal pathway.

Key words: huangqi decoction, heavy ion radiation, kidney apoptosis, Bcl-2/NF-κB signal pathway, rat