[Effects of astaxanthin combined with aerobic exercise on renal aging of rat induced by D-galactose and its mechanism].

Objective: To study the effects and mechanisms of astaxanthin combined with aerobic exercise on renal senescence of rat induced by D-galactose. Methods: Sixty 3-month-old SPF SD rats were divided into control group (C group), acute senescence group (S group), astaxanthin+acute senescence group (AS group), aerobic exercise+acute senescence group (ES group), astaxanthin+aerobic exercise+acute senescence group (AES group), by two-factor two-level 2×2 factorial design with 12 rats in each group. Acute senescence model of rat was establshed by intraperitoneal injection with 100 mg/(kg·d) D-galactose, and the intervention was conducted with 20 mg/(kg·d) astaxanthin and/or aerobic exercise with 60% VO2max for 6 weeks. The histopathological/ultrastructural changes of the kidney were observed by light microscope/electron microscope; the levels of SOD, γ-GCS and MDA were detected by ELISA, and LDF in kidney was determined by fluorescence colorimetry; the protein expression of Nrf2 signaling pathway was detected by immunohistochemistry. Results: Compared with AS and ES group, in AES group, the improvement of renal tissue morphology/ultrastructure was more significant; LDF was decreased significantly (P＜0.01); SOD activity was significantly increased (P＜0.01); γ-GCS was significantly higher than that of AS group, but not significantly different from that of ES group (P＞0.05); there was no significant difference in MDA between groups (P＞0.05); the levels of Nrf2 and p-Nrf2 were increased significantly (P＜0.05, P＜0.01); HO-1 was significantly higher than that of ES group(P＜0.05), but not significantly different compared with that of AS group(P＞0.05). Conclusion: Astaxanthin combined with aerobic exercise can delay aging process of kidney, its mechanism may be that the combination regulate the protein expression in Nrf2 signaling pathway, Ⅱ detoxifying enzymes and antioxidant enzyme activity, and improve oxidative stress in kidney of rat induced by D-galactose.