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Wang H.-L.,Institute of Nephrology of Nanjing Command | Li Y.,Institute of Nephrology of Nanjing Command | Tian J.,Institute of Nephrology of Nanjing Command | Hu W.-F.,Institute of Nephrology of Nanjing Command | Zhang J.-Y.,Institute of Nephrology of Nanjing Command
Medical Journal of Chinese People's Liberation Army

Objective To investigate the effects of high strength exhaustive exercise on apoptosis of renal tubular epithelial cells (TECs) and expression of hypoxia-inducible factor-1 α (HIF-1 α) in rats and the effect of intervention of total ginsenoside. Methods Thirty-five male Sprague-Dawley rats were randomly divided into five groups (7 each): control group (CTL), model group (divided into two subgroups: M2 and M24); total ginsenoside group (divided into two subgroups: G2 and G24). The animal model of exhaustive exercise induced acute kidney injury (AKI) was reproduced by forcing the rats running on the treadmill followed by exhaustive swimming according to the protocol. Ginsenoside [100g/(kg.d)] was intragastrically gavaged 5 days before exhausting exercise in rats of G2 and G24, and the same volume of water was given to rats in model and CTL groups. Apoptosis of TECs was observed under microscope after TUNEL staining. The expressions of caspase-3 and HIF-1a in TECs were analyzed by immunohistochemical staining. The protein expression of caspase-3 and HIF-1a was determined by Western blotting. Results In model group, 11 out of 14 rats were stranded on treadmill, and the time of exhaustive swimming was significantly shorter as compared with that of CTL group; but the endurance increased significantly in total ginsenoside groups, in which only 6/14 rats were stranded on treadmill, and the swimming time was significantly longer compared with model group (P<0.05). The TUNEL-positive apoptotic cells increased in M2 and M24 groups (especially in M24 group), and they were mainly distributed in those TECs at the corticomedullary junction in model groups; but the number of TUNEL-positive cells decreased significantly in total ginsenoside group (G2, G24) as compared with model group (P<0.05). Immunohistochemical analysis showed that caspases-3 and HIF-1α were only weakly positive in CTL group, but significantly upregulated in M2 group, and it was stronger in M24 group. Strongly positive staining of caspase 3 was observed in the brush border of injured TECs, and it decreased significantly in total ginsenoside group (G2 and G24). On the other hand, the level of HIF-1α expression increased in these groups compared with the model group. Western blotting showed trace expression of caspases-3 and HIF-1α in CTL group, but the level of caspases-3 expression significantly increased in model group (2.7-fold increase in M2 group, 3-fold increase in M24 group), while the caspases-3 expression levels were reduced about 58% and 61%, respectively, in G2 and G24 groups compared with M2 or M24 group. The HIF-1α expression increased to some extent in model group (M2 or M24), but HIF-1α expression increased rapidly in early stage, and it was in a high level in G24 in total ginsenoside group. Conclusions Exhaustive exercise may induce renal TECs apoptosis and increase caspases-3 expression; total ginsenosides can protect the TECs against injury by down-regulating caspases-3-dependent apoptotic signaling and rapid increase in HIF-lα expression. This might be one of the mechanisms of protection of tubular damage in acute kidney injury induced by exhaustive exercise by total ginsenosides. Source

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