The Effect Of CAV-1 Regulation Of AT₁R On Acute Kidney Injury Induced By Paraquat In Rats

Objective To observe the changes of the expression of BUN,SCr,IL-18 in serum and CAV-1,AT1R and IL-18 mRNA and protein in renal tissue in rats with acute kidney injury induced by paraquat poisoning after intragastric administration of losartan.To explore whether CAV-1 has a certain effect on the kidney RAS of rats with paraquat poisoning,whether it plays a protective role.Methods 72 male Sprague-Dawley rats were randomly divided into control group(NS group),paraquat poisoning group(PQ group)and losartan group(LT group)by random number method.On the first day of the experiment,100mg/kg paraquat solution was used in the LT group and the PQ group to establish the acute kidney injury model,and the same amount of normal saline was used in the NS group to establish the blank control.After that,rats in the LT group were given 60mg/kg of losartan solution daily,while rats in the PQ group and the NS group were given the same amount of normal saline daily and kept in routine feeding.Changes in general conditions of rats in each group were observed daily.Rats were treated in four batches at day 1,3,7 and 14,with 6 rats in each batch:abdominal cavity was opened after anesthesia,and renal tissue and abdominal aorta blood were taken for serum.HE staining was performed on the renal tissues of each group,and pathological changes were observed and graded.The concentration of BUN and SCr in serum of rats was detected by automatic biochemical analyzer.Serum IL-18 level was detected by ELISA.qRT-PCR was used to detect the mRNA expression of CAV-1,ATiR and IL-18 in renal tissue of rats.Immunohistochemistry was used to detect the positive expression rates of CAV-1,AT1R and IL-18 protein in renal tissue of rats.Western-blot was used to determine the expression levels of CAV-1 and AT1R protein in rat kidney.Results(1)Renal histopathology showed clear and complete renal unit structure in the NS group,and no edema,hyperemia and inflammatory cells were found in renal interstitium.In the PQ group,a large number of infiltrating inflammatory cells were observed in the renal interstitium,with edema and hyperemia.In the renal cortex,the renal tubular epithelial cells showed obvious vacuolar degeneration and swelling,and even flaky and focal necrosis.The infiltration of inflammatory cells in renal interstitium,edema and congestion,and vacuolar degeneration of renal tubular epithelial cells in the LT group were less severe than those in the PQ group.(2)Blood biochemical results of rats showed that the levels of BUN and SCr in serum of the PQ group and the LT group were higher than those of the NS group at each time point(P<0.05).On day 1,there was no significant difference between the LT group and the PQ group in serum BUN and SCr levels.From day 3,the serum BUN and SCr levels in LT group were lower than those in the PQ group(P<0.05),and there was an overall downward trend.(3)In the rat serum ELISA,according to the results of the PQ group and the LT group rats each point in time the concentration of IL-18 were higher than in the NS group(P<0.05),the LT group and the PQ group rats on day 1 serum IL-18 concentration has no obvious difference,since day 3,the LT group the concentration of serum IL-18 rats were below the PQ group(P<0.05),and a general downward trend.(4)In the rat kidney tissue qRT-PCR,according to the results of the PQ group and the LT group rats at various time points of CAV-1,ATiR,IL-18 mRNA expression was higher than that of the NS group(P<0.05),the LT group of rats in the kidney tissues of CAV-1 and ATiR mRNA expression quantity at various time points were below the PQ group(P<0.05),and a general downward trend,the LT group rats IL-18 mRNA expression in renal tissue volume and the PQ group no significant difference in day 1.From day 3,the expression level of IL-18 mRNA in the kidney tissues of the LT group was lower than that of the PQ group(P<0.05),and a general downward trend.(5)In the rat kidney immunohistochemical results show that the PQ group and the LT group rats at various time points in the kidney tissues of CAV-1,AT1R,IL-18 protein expression was higher than that of the NS group(P<0.05),the LT group of rats in the kidney tissues the expression of CAV-1,AT1R,the IL-18 protein quantity and the PQ group no significant difference in day 1,since day 3,the LT group of rats in the kidney tissues the expression of CAV-1,AT1R,IL-18 protein quantity were below the PQ group(P<0.05),and a general downward trend.(6)Western-blot results of renal tissue showed that the expression levels of CAV-1 and AT1R protein in renal tissue of the PQ group and the LT group were all higher than those of the NS group at all time points(P<0.05),and that of the LT group at all time points was lower than that of the PQ group(P<0.05).Conclusion Paraquat poisoning can result in renal injury,and result in abnormal increase of CAV-1,AT1R and IL-18 in rats,.Losartan,an ATiR antagonist,was used to reduce the expression of CAV-1,ATiR and IL-18,and to alleviate renal injury.CAV-1 may inhibit RAS mediating renal inflammatory response in rats with paraquat poisoning by combining with AT1R,thus providing renal protection.