肢体缺血后处理对糖尿病大鼠脑缺血再灌注损伤线粒体结构和功能的影响

Effects of limbs ischemic postconditioning on mitochondria structure and function after cerebral ischemic reperfusion in diabetic rats

目的探讨肢体缺血后处理(I-PostC)诱导的远隔器官I-PostC(RPostC)对糖尿病大鼠局灶性脑缺血再灌注(I/R)损伤线粒体结构和功能的影响。方法链脲佐菌素空腹腹腔注射制作糖尿病大鼠模型,线栓法闭塞大脑中动脉(MCAO)制作局灶性I/R大鼠模型。造模成功的40只雄性SD大鼠分为4组:空白对照组、假手术组、I/R组,RPostC组,每组10只。I/R6h后取脑组织行HE染色观察,测定线粒体丙二醛(MDA)含量、超氧化物歧化酶(SOD)、Na+/K+-ATP酶、Ca2+-ATP酶和谷胱甘肽过氧化物酶(GSH-Px)活性,观察线粒体超微结构的改变。结果I/R组线粒体MDA含量[(4.99±1.25)nmol/mgprot]较空白对照组和假手术组明显升高(均P<0.01),SOD[(72.52±13.07)U/mg]、Na+/K+-ATP酶[(3.17±0.34)μmolPi/(mg.h)]、Ca2+-ATP酶[(1.56±0.23)μmolPi/(mg.h)]和GSH-Px活性[(22.66±5.29)U/mg)]明显降低(均P<0.01);与I/R组比较,RPostC组MDA含量[(3.58±0.91)nmol/mg]明显降低(P<0.05),SOD[(99.57±17.80U/mg)]、Na+/K+-ATP酶[(5.89±0.53)μmolPi/(mg.h)]、Ca2+-ATP酶[(3.16±0.31)μmolPi/(mg.h)]和GSH-Px活性[(31.72±6.14)U/mg)]明显升高(P<0.05～0.01);RPostC明显减轻I/R引起的脑组织和线粒体病理损伤程度。结论肢体I-PostC诱导的RPostC对糖尿病大鼠脑和线粒体有明显的保护作用。其机制可能与其增加SOD、Na+/K+-ATP酶、Ca2+-ATP酶和GSH-Px活性有关。

Objective To investigate effects of limbs ischemic postconditioning induced remote postconditioning （RPostC） on mitochondria structure and function after focal cerebral ischemic reperfusion （I/R） injury in diabetic rats. Methods The diabetic rats models were induced by injecting streptozotocin into abdominal cavity. I/R rats models were made by MCAO with thread. Forty male SD rats models were assigned to 4 groups ： control group ; sham operation group ; I/R group ; RPostC group （ n = 10 ） . 6 h after the reperfusion, the brains were obtained for HE staining. The mitchondria were isolated and content of MDA, the activities of SOD, Na^＋/K^＋ -ATPase, Ca^2 ＋ -ATPase and GSH-Px were tested. Morphological changes of neuronal mitochondria were observed by electronic microscope. Results In the I/R group,the content of mitchondria MDA[ （4.99 ± 1.25 ） nmol/mgprot] were markedly increased （P〈0.01） and the activities of mitochondria SOD [ （72.52 ± 13.07） U/mg] ,Na^＋/K^＋-ATPase[ （3.17 ±0.34） μmolPi/（mg·h） ], Ca^2＋-ATPase [（1.56±0.23 ）μmolpi/（ mg·h）] and GSH-Px [（22.66± 5.29 ） U/mg） ] were decreased significantly （ all P 〈 0.01 ）. Compared with the I/R group, the content of mitchondria MDA [（3.58±0.91 nmol/mg）] of the RPostC group were markedly decreased and the activities of mitochondria SOD[ （99.57±17. 80 U/mg）], Na^＋/K^＋ -ATPase [ （5.89±0.53 ）μmolPi/（ mg·h ） ], Ca^2＋ -ATPase [（3.16 ±0.31 ）μmolPi/（ mg·h） ] and GSH-Px [（31.72 ± 6.14） U/mg）] were enhanced （P 〈 0. 05 - 0.01 ）. RPostC reduced the brain and mitochondria pathological damage induced by cerebral I/R. Conclusions RPostC can be induced by transient limbs ischemia and have an obvious protective effect on brain and mitochondria damage in diabetic rats. The mechanism of protection may be related to increase of the activities of SOD,Na^＋/K^＋ -ATPase, Ca^2＋ -ATPase and GSH-Px.