Effect Of Long Non-Coding RNA MALAT1 On Renal Ischemia-Reperfusion Injury

Objectives:(1)To investigate the relationship between the expression of long non-coding RNA MALAT1 on ischemia-reperfusion injury in mice kidney and the renal function(Scr and BUN).(2)In vitro,to explore the possible mechansim of MALAT1 on the renal inflammation induced by hypoxia by knocking down MALAT1 in HK2 cells.Methods:(1)18 mice were randomly divided into sham operation group(sham),ischemia-reperfusion group(including IR6h?IR12h).Renal ischemia—reperfusion injury was induced by clamping the bilateral renal pedicles for 40 min,and then reperfused for 6 and 12 hours.The serum samples were collected to test the renal function(Scr?BUN).The kindeys were removed for determination of MALAT1 mRNA by qRT-PCR.(2)HK2 cells were transfected with MALAT1 siRNA or negative control by lipofectamine(Lipofectamine 2000).After 24 hours,HK2 cells were treated with DMDM/F12 containing cobalt chloride(Cocl2,200?mol/L)to induce the hypoxia condition.HK2 cells were divided into four groups :(1)negative control;(2)siMALAT1 group;(3)negative control+Cocl2;(4)siMALAT1+Cocl2.After 3 hours treated by Cocl2,HK2 cells were collected to determinate the expression of MALAT1 by RT-PCR.The HIF-1? and NF-?B(p65 /p-p65)protein were detected by Western blot after 24 hours treated by Cocl2.The contents of IL-6 and TNF-? in the HK2 cells were detected by ELISA.Results :(1)In mice,the expression of MALAT1 in renal tissues in IR(6h/12h)groups was significantly higher than those in sham group(p<0.05).The Scr and BUN levels in the IR6 h group and the IR12 h groups were significantly higher than the sham group(p<0.05).(2)In HK2 cells,compared with the control group,the expression of MALAT1 in the Cocl2-treated groups(0.5h?1h?3h?6h)was significantly higher(p<0.05),but in the Cocl2-treated groups(12h?24h),there was no significant change.Compared with the siNC group,siMALAT1 group had a better inhibitory effect of MALAT1 mR NA(p<0.05).The expression of protein HIF-1? and NF-?B(p-p65/p65)in the siM ALAT1+Cocl2 group weresignificantly higher than the siNC+Cocl2 group(p<0.05).IL-6 and TNF-? of the siMALAT1+Cocl2 group were significantly increased(p<0.05)compared with the siNC+Cocl2 group.Conclusions :(1)The expression of lnc RNA MALAT1 was increased in the model of renal ischemia-reperfusion injury,which was consistent with the renal function(Scr and BUN).(2)In HK2 cells,siMALAT could significantly decrease the expression of MALAT1.(3)In HK2 cells treated with Cocl2,MALAT1 knocking down by siRNA increases the level of HIF-1??NF-?B(p-p65/p65)and the level of IL-6?TNF-?.MALAT1 may regulate ischemia-reperfusion induced inflammatory process by HIF-1?/NF-?B pathway in the HK2 cells.