[Effect of PKC inhibitor on renal podocyte slit diaphragm protein expression in exhausted rats].

Objective: To investigate the expression level of podocyte slit diaphragm protein in rats after one-time exhaustive exercise, to explore the effect of PKC inhibitor on the protein expression level, and to reveal the mechanism of PKC in the formation of exercise-induced proteinuria. Methods: Thirty male SD rats were randomly divided into control group (C), exercise group (E) and exercise combining with PKC inhibitor group (EPI), with 10 rats in each group. Rats in group E and EPI performed one single bout of exhaustive exercise (25 m/min), rats in group EPI were intraperitoneally injected with a PKC inhibitor (chelerythrine, 5 mg/kg) 1 day and 1 hour before exercise respectively, while rats in group C and E were injected with the same volume of saline. Results: ①Compared with group C, the levels of urine protein, uric acid, urine sugar, blood urea, and blood uric acid of rats in group E were increased significantly (P＜0.05), the level of blood glucose was reduced significantly (P＜0.01), and renal ROS production was increased significantly (P＜0.01). The expressions of nephrin and podocin protein in renal tissue were decreased significantly (P＜ 0.05), while the expressions of PKC, Nox2, and Nox4 protein were increased significantly (P＜0.05). ②Compared with group E, the levels of urinary protein,urine glucose and blood urea in EPI group were decreased significantly (P＜0.05), the level of blood glucose was increased significantly (P＜0.01), renal ROS production was reduced significantly (P＜0.01). the expressions of nephrin and podocin protein in renal tissues of the EPI group were increased significantly (P＜0.05), while the expressions of PKC and Nox2 protein was reduced significantly (P＜0.05, P＜0.01). Conclusion: One-time exhaustive exercise can down-regulate the expressions of nephrin and podocin through PKC/Nox/ROS pathways in the kidney of rats; PKC inhibitor alleviates the decrease in the expression of podocyte slit diaphragm protein caused by exhaustive exercise, and prevents the occurrence of exercise-induced proteinuria.

[Effect of swimming training on the expression of PKC δ/p66Shc protein in mouse myocardium].

Objective: To investigate the effects of different intensity of swimming training on p66Shc protein in mouse myocardium. Methods: Fifty Kunming mice were randomly divided into control group (Group C), weight-bearing swimming group (Group E), weight-bearing swimming + drug group (Group ER), non weight-bearing swimming group (Group P), non weight-bearing swimming + drug group (Group PR), with 10 mice in each group. Group C did not exercise. Groups E, ER, P, and PR received swimming training for 4 weeks. Groups E and ER performed weight-bearing swimming with a 3% body weight, and Group P and Group PR were swimming without weight-bearing, 60 min/d, 6 times/w. Mice in ER and PR groups were injected intraperitoneally with Rottlerin (0.3 mg/kg), a PKCδ inhibitor, before the last two exercises. Groups C, E, and P were injected with the same dose of normal saline. Samples were collected after training finished for 24 hours. The protein expressions of PKCδ, P-PKCδ, P66Shc, P-P66shc and NOX2 were detected by Western blot; PKCδ and P66Shc were detected by immunoprecipitation; malondialdehyde (MDA), reactive oxygen species (ROS) and superoxide dismutase (SOD) in myocardium and serum were analyzed by biochemistry. Results: Compared with Group C, the protein expressions of PKCδ, P-PKCδ, P66Shc, P-P66shc and NOX2 in Group E were increased significantly (P＜ 0.01), the serum and myocardial MDA levels, myocardial ROS were increased significantly (P＜0.05 or P＜0.01), and the myocardial SOD activity was decreased (P＜0.01), the PKCδ, P-PKCδ, P-P66shc and NOX2 in Group P were increased significantly (P＜0.05 or P＜0.01), and the myocardial SOD activity was enhanced (P＜0.05). Compared with Group E, the protein expressionS of PKCδ (P＜0.01), P-PKCδ (P＜0.01), P66Shc (P＜0.05), P-P66shc (P＜0.01), NOX2 (P＜0.05) in Group ER was decreased significantly, the protein expression of P66Shc in Group P was decreased significantly (P＜0.05), the myocardial MDA (P＜0.01) and ROS (P＜0.05) were decreased, and the activity of SOD was enhanced (P＜0.01). Compared with Group P, the protein expressions of PKCδ, P-PKCδ and P-P66shc in Group PR were decreased significantly (P＜0.01), while the expression of NOX2 was increased (P＜0.05). Conclusion: Both swimming training of two intensities promoted the increase of PKCδ protein and its phosphorylation in mouse cardiomyocytes. High-intensity swimming training could significantly enhance the expression and phosphorylation level of p66Shc protein, resulting in the production of ROS and the decrease of antioxidant enzyme activity. Low-intensity swimming training enhanced the phosphorylation of p66Shc, but did not promote its protein expression, resulting in the enhancement of myocardial antioxidant capacity and exercise adaptation.