| Objective: 1. To observe the changes of renal histology , ultrastructure, the extent of neutrophil infiltration and renal function . 2. To investigate the expression changes of MMP-2, MMP-9 and their effects on renal histological damage and the changes of renal function, to reveal the mechanism of action of MMP-2, MMP-9. 3. To investigate the expression changes of p38MAPK,and to explore its induction effect on the expression changes of MMP-2, MMP-9 after renal ischemia-reperfusion. 4. To investigate the effects of minocycline on the expression of MMP-2, MMP-9 and p38MAPK and its protective effects on renal histological damage and renal function,to reveal the protection mechanism of minocycline on renal ischemia-reperfusion.Methods: 72 male Sprague-Dawley rats which weight 220g~260g were randomly divided into three groups: Con (Con) group, ischemia-reperfusion(IR) group and minocycline (M) group.There are 24 rats in each group and 6 rats for each of the four phases (6h, 12h, 24h, 72h). Con group: Resecting the right kidney without occluding the left renal artery.IR group: 45 minutes after the left renal artery occlusion on the basis of the right renal resection, we restored perfusion under modeling of ischemia reperfusion injury. M group: 36 h before operation minocycline (45mg/kg) were administered via nasogastric tube and then 22.5mg/kg every 12h for a total of four doses. Renal histological and ultrastructural changes were observed through light microscope and transmission electron microscope.Myeloperoxidase (MPO) activity and serum creatinine (Scr)were determined to assess the extent of the injury for neutrophil infiltration and renal function; and two-step immunohistochemical methods were used to detect the expression of MMP-2, MMP-9 and p38MAPK . Analysis of variance and dependability were taken on the data.Results:1.There were significant pathological changes in renal histology and ultrastructure in IR group compared with Con group,the most severity damage showed up at 24h after reperfusion,and significant improvement was found in M group compared with IR group .2.The MPO activity in IR group increased remarkably compared with Con group(P<0.01), peaked at 24h, and it was distinctly lower in M group than that in IR group(P<0.05).3.Compared with Con group, the level of Scr in IR group elevated at 6h of reperfusion (106.33±12.74μmol/L), peaked at 24h(201.33±21.52μmol/L) and decreased at 72h(90.17±15.87μmol/L), and there was significant difference between the two groups (P<0.01).The level of Scr in M group was lower than that of IR group (P<0.01).4.The expression of MMP-2 was gradually upregulated after renal ischemia-reperfusion, peaked at 24 h(34.61±6.08%) (P<0.05 vs Con group), and it was distinctly lower in M group than that in IR group at 6h, 12h and 24 h (P<0.05).5.The expression of MMP-9 was gradually upregulated after renal ischemia-reperfusion, peaked at 24 h(36.05±4.75%) (P<0.05 vs Con group), and it was distinctly lower in M group than that in IR group at 6h, 12h and 24 h (P<0.05).6.The expression of p38MAPK was gradually upregulated after renal ischemia-reperfusion, peaked at 12 h(39.83±5.23%) (P<0.05 vs Con group), and it was distinctly lower in M group than that in IR group at 6h, 12h (P<0.05).7.In IR group, the expression of MMP-2 protein was positively correlated with the level of Scr and the MPO activity(r=0.763,P <0.01;r=0.752,P <0.01); the expression of MMP-9 protein was positively correlated with the level of Scr and the MPO activity (r=0.874, P <0.01;r=0.693,P <0.01); the expression of p38MAPK protein was positively correlated with that of MMP-2 and MMP-9( r=0.585,P<0.01; r=0.598,P<0.01).Conclusions:1.Ischemia-reperfusion caused the major injury of nephridial tissue , enhanced neutrophil infiltration in the renal tissue, induced the aggravation of renal function and initiated the renal failure.2.The expression of MMP-2 and MPP-9 were gradually upregulated after renal ischemia-reperfusion, they aggravated neutrophil infiltration and injury of nephridial tissue through cooperating to degrade extracellular matrix, induced the aggravation of renal function.3.The expression of p38MAPK was gradually upregulated after renal ischemia-reperfusion,and was positively correlated with that of MMP-2,MMP-9 ,it reveales that p38MAPK can induce the expression of MMP-2 and MPP-9.4.Minocycline could relieve the injury of nephridial tissue caused by ischemia-reperfusion, inhibit neutrophil infiltration , protect renal function.Minocycline decreased the expression of MMP-2, MMP-9 wich induced by p38MAPK, it may be the mechanism that Minocycline could relieve renal ischemia-reperfusion injury.
|
PDF Full Text Request