| Objective:Mitochondrial division is a key process of renal ischemia-reperfusion injury,and dynamic related protein 1(Drp1)is a key protein that promotes mitochondrial division.Under stress conditions such as ischemia and hypoxia,a large amount of Drpl transfers from the cytoplasm to the mitochondrial outer membrane fission site,thereby driving the contraction and division of the mitochondrial outer membrane and causing mitochondrial fission.As a Drpl inhibitor,mdivi-1 inhibits the outer membrane assembly of Drpl and inhibits mitochondrial division.In this study,mdivi-1 was intramuscular injected 2 hours before modeling to investigate the effect of mdivi-1 on renal ischemia reperfusion injury and its specific mechanism by detecting renal function(creatinine,urea nitrogen),inflammatory factors,immunohistochemistry(Drp1,Cytc)and HE pathological staining.Methods: Thirty 8-week-old male Sprague-Dawley(SD)rats were randomly divided into 5 groups using the random number table method,which were sham operation group(Sham group)and ischemia-reperfusion group(I/R group),Mdivi-1 low-dose group(M-L group),Mdivi-1middle-dose group(M-M group),Mdivi-1 high-dose group(M-H group),8 mice per group(n=8).I/R group: Rats were anesthetized with intraperitoneal injection of 10% chloral hydrate,and bilateral renal arteries were clamped with a non-traumatic vascular clamp for 45 minutes to make a rat ischemia-reperfusion injury model.Sham group:Rats underwent the same surgery without renal artery pinch.Mdivi-1group: Mdivi-1 was injected intraperitoneally 2 hours before ischemia,and divided into low,medium and high dose groups at 12.5mg / kg,25mg/ kg,and 50 mg / kg doses,respectively.Based on the time taken to releasethe blood vessel clamp,the rats were sacrificed after 24 hours,and serum samples were retained.Automatic biochemical analyzer to detect blood creatinine and urea nitrogen levels;HE staining to observe renal pathology;ELISA to detect serum TNF-α,IL-1β levels;immunohistochemical detection of Cytc and Drp1 expression in renal tissue;TUNEL method to detect renal tubular epithelial Dead level.Results:(1)The serum creatinine and urea nitrogen of I/R group were significantly higher than those of sham group(P < 0.05).The serum creatinine and urea nitrogen levels of middle and high dose mdivi-1group were significantly lower than that of I/R group(P < 0.05)。The serum creatinine and urea nitrogen of low dose mdivi-1 group were higher than that of I/R group(P < 0.05).(2)Compared with the sham group,the renal pathology of the I / R group was compared with that of the sham group.Swelling of the renal tubules,edema of the tubular epithelial cells,necrosis,shedding,and exposed basement membranes were visible.The renal tubular injury score of I / R group was significantly higher than that of sham group(P < 0.05).In the middle and high dose Mdivi-1 group,compared with the I / R group,the renal tubular epithelial cells were significantly reduced,the renal tubular edema was reduced,and the renal tubular injury score was significantly reduced(P﹤0.05).Compared with the I/R group,the renal pathology of the Mdivi-1low-dose group was more swollen and necrotic,and the erythrocyte cast increased.The renal tissue injury score was higher than that of the I/R group.(P﹤0.05).(3)The expression level of drp1 protein in I/R group was significantly higher than that in sham group(P < 0.05).The expression level of Drp1 in the medium and high dose Mdivi-1 group was significantly lower than that in the I/R group,with a significant difference(P <0.05),the expression level of Drp1 in the low-dose Mdivi-1 group was lower than that in the I/R group(P> 0.05).(4)The expression level of cytc in I/R group was significantly higher than that in sham group,and the difference was significant(P <0.05).Medium and high dose mdivi-1group Cytc decreased significantly compared with the I/R group(P<0.05).Cytc in the low-dose mdivi-1 group was significantly higher than that in the I/R group(P<0.05).(5)Apoptosis index of renal tubular epithelial cells in I/R group was significantly higher than that in Sham group,the difference was significant(P <0.05).Apoptosis of renal tubular epithelial cells in Mdivi-1 medium and high dose groups was significantly higher than that in I/R group There was a significant decrease,and the difference was significant(P <0.05).The apoptosis index of renal tubular epithelial cells in the low dose group of mdivi-1 was higher than that in the I/R group(P<0.05).(6)The levels of TNF-α and IL-1β in I/R group were higher than in sham group(P < 0.05).TNF-α and IL-1β in middle and high dose mdivi-1 group decreased significantly compared with that in I/R group(P<0.05).Compared with the I / R group,the serum TNF-α and IL-1β levels were increased in the low-dose Mdivi-1 group(P< 0.05).Conclusion: Renal ischemia-reperfusion injury can induce excessive mitochondrial division induced by Drp1,resulting in a large amount of Cytc release,leading to renal tubular epithelial cell apoptosis,and at the same time,it can promote the release of inflammatory factors and cause renal damage and dysfunction.Mdivi-1,as a mitochondrial inhibitor,can inhibit the excessive division of mitochondria mediated by Drp1,reduce the release of Cytc from mitochondria,relieve apoptosis and release of inflammatory factors,and improve renal function. |
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