The Role Of Macrophage Polarization In Acute Kidney Injury Induced By Overtraining

Objective: The acute kidney injury is often induced by overtraining(OTIAKI),if not handle in time may develop into irreversible kidney damage or threat to life,but the specific mechanism is not fully clear.Therefore,the study of its pathogenesis has great significance for the treatment of kidney damage and the improvement of the quality of life.Our study is aim to develop overtraining-induced acute kidney injury model by swimming to exhaust in rats to evaluate the differentiation trend in renal tissue during OTIAKI and to provide reference for clinical research。Methods:1.35 male Wistar rats,weighting aaaaa200-220 g,the rats were divided into three groups by using random number table method : Normal control group(controls,CN,n=5),Simple exhaustive exercise group(acute kidney injury,AKI,n=15),Cobra toxicity factor intervention group(CVF,n=15).In addition to CN group,according to the observation time was divided into three subgroups: immediate group,6h group,24 h group,each time point 5 rats.2.The rats were anesthetized at various time points after exhaustive exercise,collecting inferior vena cava blood and storing in anticoagulant tubes to be tested.Gather the double kidney,the left kidney placed in EP tubes saving in-80℃and right kidney placed into polyformaldehyde saved in 4 ℃,to be next tested process.3.Pathological changes of renal tissue structure were observed by light microscope.4.Biochemical instrument to detect creatinine,urea.5.Western blot analysis and immunohistochemical detection of CD68,CD163 were used.6.Statistics analysis : IBM SPSS21.0 was used for statistics,and the mean standard deviation(x± s)was expressed.One-way ANOVA was used for the comparison between groups,and P < 0.05 was considered as the test level.Results:1.Groups of blood BUN,Cr changes: the level of Cr and BUN in AKI group was higher than that of CN group(P < 0.05).The CVF group decreased compared with the AKI group in the same time point,but was higher than that of CN group(P < 0.05).2.Pathological changes: The normal control group had no obvious pathological changes in renal tissue.The renal tissue structure of AKI and CVF in the immediate and 6h groups was slightly pathological changes.The pathological changes of 24 h group was obvious.3.Injury score: Compared with the CN group,the injury score was significantly increased in the AKI group(p<0.05).Compared with AKI group,CVF score decreased at the same time point(P < 0.05).4.Western blot: The expression of CD163 and CD68 was not obvious in the CN group;Values of CD68/β-Actin and CD163/β-Actin were higher in the AKI and CVF groups than in the CN group(P<0.05).Values of CD68/β-Actin decreased compared to the same time point AKI group while CD163/β-Actin is increased compared to the same time point AKI group(P < 0.05).5.Immunohistochemical:The expression of CD163 and CD68 was not obvious in the CN group;Values of CD68 and CD163 were higher in the AKI and CVF groups than in the CN group(P < 0.05).Values of CD68 decreased compared to the same time point AKI group while CD163 is increased compared to the same time point AKI group(P < 0.05).Conclusion:1.After exhaustive swimming,the expression of CD68 in rat kidney was enhanced,and CD68 was a marker of macrophages,suggesting that macrophages were involved in the process of OTIAKI injury.2.CD68 expression was increased in early kidney injury and then decreased,while CD163 expression was progressively enhanced.It is suggest that M1-type macrophages are involved in the early damage process of OTIAKI,and M2-type macrophages may play an important role in the lately tissue reconstruction of OTIAKI.3.The expression of CD68 in snake venom factor intervention group was lower than that in AKI group at the same time point,and the expression of CD163 was higher than that in AKI group at the same time point.The results suggest that the polarization and function of macrophages are partly affected by complement.