Overtraining induces renal cell apoptosis partly through inflammatory signal pathway in exhaustive swimming rats / 中华肾脏病杂志

ABSTRACT

Objective To observe the changes in the expression of renal tissue TNF-α , NF-κB and the interrelation to renal cell apoptosis, and their influences of Inula Britannica(an inhibitor of inflammatory signal pathway) in exhausted swimming rats, and to investigate the role of inflammatory signal pathway. Methods Forty-eight male Wistar rats were randomly divided into three groups control group (CN, n=8), exhaustive swimming group (ES, n=24) and Inula Britannica group (IB, n=16). The rats of CN were quiet without swimming. The rats of ES swam to exhaustion and were sacrificed at immediately (ESI, n=8), 6 hour (ES 6 h, n=8) and 24 hour (ES 24 h, n=8) after exhanstiing swimming. The rats of IB group took orally Inula Britannica at the dose of 25 ml/kg body weight at 24 h before swimming and then swam to exhaustive state. The rats of IB group were sacrificed at 6 hour (IB 6 h, n=8) and 24 hour (IB 24 h, n=8) after exhaustiing swimming. The renal cell apoptosis was measured by the method of terminal-deoxynucleotidyl transferase mediated d-UTP nick end labeling (TUNEL). The expression of TNF-α in renal tissue was examined by immunohistochemistry. The changes of NF-κB in renal tissue were measured by flow cytometry and immunnhistochemistry. The interrelation between TNF-α and NF-κB was analyzed by Pearson method, and the interrelation between TNF-α, NF-κB and renal tissue cell apoptosis was analyzed by Spearman method. Resulls The number of renal tissue apoptotic cells was increased progressively from ESI to ES 24 h rats (P <0.05). Immunohistochemistry staining showed that the positive expressions of renal tissue TNF-α and NF-κB were increased progressively at 0 h (0.136±0.009, 0.129±0.011), 6 h (0.171±0.011, 0.166± 0.009) and 24 h (0.229±0.008, 0.218±0.019) after exhaustiing swimming in ES compared with control group (0.109±0.010, 0.095±0.010) ( all P<0.05). The similar changes of renal tissue NF-κB was also revcalved by flow cytometry. The expression of TNF-α was positively correldted with NF-κB (r=0.955, P<0.01 ), and renal cell apoptosis was also positively correlated with TNF-α and NF-κB (r =0.953, r=0.939, P<0.01) in ES rats. Pretreatment with Inula Britannica, inhibited the up-regulation of expressions of renal tissue TNF-α (6 h0.142±0.012, 24 h0.130±0.010) and NF-κB (6 h0.138±0.010, 24 h0.136±0.011 ) induced by exhausting swimming. Conclusion Overtraining can induce the up-regulating expressions of renal tissue TNF-α and NF-κB, and Inula Britannica can partly counter the above changes in exhaustied swimming rats, which may be one important mechanisms of overtraining-induced renal tissue cell apoptosis and the anti- apoptosis effect of Inula Britannica.