The Role Of Mitochondrial Permeability Transition Pore In Ischemic Post-conditioning For Counteracting Small Intestinal Ischemia-reperfusion Injury In Rabbits

ObjectiveTo investigate the role of mitochondrial permeability transition pore(mPTP)in ischemic post-conditioning for counteracting small intestinal ischemia-reperfusion injury in rabbits.MethodsForty New Zealand rabbits were randomly divided into sham-operated group(Sham group),ischemia-reperfusion group(I/R group),ischemic post-conditioning group(IPO group),mPTP inhibitor cyclosporine A group(CsA group),and ischemic post-conditioning+ mPTP agonist atractyloside group(IPO+Atr group).Parts of small intestine tissues were collected from each group of rabbits after intervention for Hematoxylin-Eosin(HE)staining.Malondialdehyde(MDA)activity in small intestine tissue was detected by the relevant kit;mitochondria were isolated and mPTP opening was detected by relevant kits;intestinal mucosal injury was observed by Chiu’s grade 6scoring method;the apoptosis of intestinal epithelial cells was detected by TUNEL assay.ResultsCompared with Sham group,mPTP opening in I/R group was significantly increased[(1.37 ± 0.16)in I/R group vs.(3.53 ± 0.36)in Sham group,P < 0.05];MDA activity was significantly increased [(0.98±0.14)nmol/mg in I/R group vs(0.34±0.03)nmol/mg in Sham group,P<0.05];intestinal mucosa score was significantly increased [(4.66±0.41)in I/R group vs(0.92±0.58)in Sham group,P<0.05];apoptotic index of intestinal cells was significantly increased [(60.34±6.02)% in I/R group vs(4.65±1.68)% in Sham group,P<0.05].Compared with I/R group,mPTP opening in IPO group and CsA group were significantly decreased [(2.32±0.23)in IPO group or(2.62±0.18)in CsA group vs.(1.37±0.16)in I/R group,P<0.05];MDA activity was significantly decreased [(0.55±0.04)nmol/mg in IPO group or(0.62±0.06)nmol/mg in CsA group vs(0.98±0.14)nmol/mg in I/R group,P<0.05];intestinal mucosa score was significantly decreased [(3.25±0.27)in IPO group or(3.52±0.55)in CsA group vs(4.66±0.41)in I/R group,P<0.05];apoptotic index of intestinal cells was significantly decreased [(28.33±3.20)% in IPO group or(20.49±4.10)% in CsA group vs.(60.34±6.02)% in I/R group,P<0.05].Compared with IPO group,mPTP opening in IPo+Atr group was significantly increased [IPO+Atr group(1.05±0.16)vs IPO group(2.32±0.23),P<0.05];MDA activity was significantly increased[(1.08±0.18)nmol/mg in IPo + Atr group vs(0.55±0.04)nmol/mg in IPO group,P<0.05];intestinal mucosa score was significantly increased [(4.57±0.32)in IPO + Atr group vs(3.25±0.27)in IPO group,P<0.05];apoptotic index of intestinal cells was significantly increased [(40.35±2.18)% in IPO + Atr group vs(28.33±3.20)% in IPO group,P<0.05].ConclusionThe mechanism of ischemic post-conditioning for counteracting intestinal ischemia-reperfusion injury in rabbits may be associated with the inhibition of mitochondrial permeability transition pore opening.