| Objective: Over-training-induced acute kidney injury (OTIAKI) has become an important disease hazarded to human health. More and more attention has been paid to the point in recent years. However the clinical diagnosis and treatment have little progression because the damage mode and mechanism remain unclear. Therefore, in-depth study of the pathogenesis and seeking for new early biological factors have become an important topic of clinical medicine, sports medicine and military medicine .The studies show that kidney injury molecule-1(KIM-1) and Interleukin-6(IL-6) are the important biological markers for early diagnosis of AKI. In the present study, we established the animal model of over-training-induced acute kidney injury by swimming to exhaustion in rats. We observed the expression changes of KIM-1 and IL-6, and the relationship between changes with renal damage, and the influences of Anisodamine meanwhile.Methods: (1) Select 56 healthy SD rats, weighing 200-220g. The rats were randomly divided into three groups: control group (CN, n = 8), exhaustive swimming (ES, n =24) and Anisodamine group (AD, n = 24). The rat of ES swimed to exhaustive state and sacrificed at 1h (ES 1h), 6h (ES 6h) and 24h (ES 24h). The rats of AD received intra-peritoneal injection of Anisodamine at the dose of 10mg/kg body weight at 20 minutes before swimming and then swimed to exhaustive condition. The rats of AD were sacrificed at 1h (AD 1h), 6h (AD 6h) and 24h (AD 24h) after exhaustive swimming. The animal model of overtraining-induced acute kidney injury was developed by exhaustive swimming. (2) After exhaustive swimming, all the rats were put into metabolic cages to collect urine for testing Kim-1. Blood samples were collected via the inferior vena cava for determining serum creatinine (Scr), blood urea nitrogen (BUN). One side of the kidney was madeinto hemogenate and preserved in -20℃to measure IL-6, KIM-1 byradioimmunoasssy;the other side kidney was put into 10% neutral formalin forHE staining and immunohistochemistic staining to observe the renalhistopathologic and the expression of Kim-1. (3) Statistical analysis: Allstatistical analysis of the experimental data were used SPSS 13.0 statisticalsoftware package, the results were expressed as mean±standard deviation (X±s). Differences are compared using single factor analysis of variance(one-way ANOVA), correlation analysis using Pearson correlation test, theP<0.05 was considered statistically significant.Results: (1) General changes: Normal control group rats could movefreely, the mental state is good, responsive, and normal diet; exhaustiveexercise group rats were unable to move, apathetic, indifferent response, lowerdiet. (2) Renal morphology: The renal tissue structure was no significantchanges in rats of control group. Promixal tubular epithelial cells swelling inES 1h and ES 6h groups; In ES 24h group congestion and edema wereobserved in glomeruli significantly, the proximal tubular epithelial cellsdegeneration, protein casts can be seen occasionally; pathological changes inAnisodamine group were lighter. (3) Blood biochemical changes: The level ofBUN and Scr increased in ES 1h rats (p<0.05); significantly increased 6 hoursafter exhaustion (p<0.05), and decreased to CN level in ES 24h (p>0.05). AD1h, AD 6h group was significantly lower than exhaustive swimming group(p<0.05 or p<0.01), but still higher than the control group (p<0.05). (4)Plasma IL-6 was significantly increased at 1h group after exhaustive exercise(p<0.05), the other groups were at normal level (p>0.05); the expression ofrenal tissue IL -6 at 1h group was significantly higher after exhaustiveexercise (p<0.01), and gradually decreased at 6h group (p<0.05), andreturned to normal levels at ES 24h. The expression of renal tissue IL-6 inanisodamine were decreased compared with ES groups (p<0.05), There wasno significant difference compared with that of N group (p>0.05). (5) UrineKim-1in ES 6h was significantly higher (p<0.05), and reached the higher level in ES 24h after exhaustion (p<0.01); AD group Kim-1 were significantly decreased compared with the exhaustive group (p<0.05), there was no Significant difference compared with the control group (p>0.05). Renal tissue Kim-1 was increased progressively from ES 1h to ES 24h. The expression of the anisodamine groups was significantly lower than the same period (p<0.05). (6) Plasma IL-6 and renal tissue IL-6 activity was positively correlated (r = 0.75, p<0.01); urine Kim-1 and renal tissue Kim-1 activity was positively correlated (r = 0.632, p<0.05); the level of urine Kim-1 were positivelycorrelated with the expression of Scr (r = 0.932, p<0.01). Conclusions: (1) The expression of renal tissue Kim-1 at ES 1h and the urine Kim-1at ES 6h are significantly increased, which suggests that Kim-1 may be an early OTIAKI biomarker, and correlated with kidney injury . (2) IL-6 at ES 1h is significantly increased, then decreased to normal levels, which suggests that IL-6 maybe play an important role in the early stages of overtraining-induced acute kidney injury. (3) Anisodamine cans significantly reduced Kim-1 and IL-6 expression, suggesting that it play a significant protective effect in rats of OTIAKI. |
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