大鼠双后肢缺血预处理对移植胰缺血-再灌注损伤的保护作用

Protective effect of ischemic preconditioning in the posterior limbs of rats on ischemic reperfusion injury of donor pancreas graft

目的:探讨大鼠双后肢缺血预处理对移植胰缺血-再灌注损伤的影响,并分析其可能的发生机制。方法:36只糖尿病大鼠随机分为缺血-再灌注组(I/R组,n=6);缺血预处理组(IPC组,n=6);缺血预处理+L-精氨酸甲基脂组(IPC+L-NAME组,n=6)和缺血预处理+8-环戊基-1,3-二丙基黄嘌呤组(IPC+DPCPX组,n=6);缺血预处理+纳洛酮组(IPC+Nal.组n=6);缺血预处理+维生素C(IPC+AA组,n=6)。检测各组再灌注前、后血糖,再灌注后2 h血清中肿瘤坏死因子ɑ(TNF-ɑ)、胰腺组织中髓过氧化酶(MPO)和丙二酰二甲醛(MDA)含量,并利用TUNEL查移植胰凋亡细胞。结果:①再灌注后,I/R组、IPC+L-NAME组、IPC+Nal.组和IPC+AA组血糖、血清中TNFɑ-、胰腺组织中MPO和MDA比IPC组含量高,IPC+DPCPX组与IPC组无显著差异。②再灌注后,I/R组、IPC+L-NAME组和IPC+AA组胰腺组织凋亡指数比IPC组高,与IPC+Nal.组和IPC+DPCPX组较IPC组无显著性差异。结论:①双后肢缺血预处理对大鼠移植胰的缺血-再灌注损伤具有保护作用,其机制可能与再灌注后一氧化氮(NO)、氧自由基和阿片样物质的释放有关。②腺苷与这种保护作用可能无关,阿片样物质介导的保护作用不是通过减少细胞凋亡途径来完成的。

Objective ： To investigate the effect of ischemic preconditioning （IPC） in the posterior limbs of rats on ischemic reperfusion （I/R） injury of donor pancreas graft, and to analyze the possible mechanism. Methods： With Group Control （n = 6, normal ） suffered with sham operation, 36 streptozocin （STZ） -induced diabetic SD rats were randomly assigned to 6 groups ： Group I/R （ n = 6 ） received pancreas transplantation alone （ PTA）, Group IPC （ n = 6 ） received pancreas transplantation alone （PTA） plus IPC, which included three cyclings of 5 minutes ischemic and 5 minutes reperfusion before reperfusing donor pancreas, Group IPC ＋ L-NAME （n = 6） , Group IPC ＋ DPCPX, Group IPC ＋ Nal. and Group IPC ＋ AA received the same treatment with Group IPC, but separately injected NOS antagonist L-arginine methyl ester （L-NAME）, adenosine A1 receptor antagonist 8-cyclopentyl-1, 3-dipropylxanthine （DPCPX）, opioid antagonist naloxone and oxygen radical scavenger ascorbic acid before IPC. The blood glucose was monitored before and after reperfusion, the TNF-α in serum, MDA and MPO in pancreatic tissue were monitored after reperfusion, and apoptotic cells were stained by TUNEL technique 2 h after reperfusion. Results： ①The blood glucose, serum TNF-α, and pancreas MDA and MPO of group I/R, Group IPC ＋ L-NAME, Group IPC ＋ Nal. and Group IPC ＋ AA were higher than those of Group IPC after reperfusion （P 〈0.01 ）. ②The apoptotic index （AI） of group I/R, Group IPC ＋ L-NAME and Group IPC ＋ AA were higher than that of Group IPC （ P 〈 0.01 ） after reperfusion. Conclusion ： ①IPC in the posterior limbs of rats can protect rat pancreas graft from I/R injury during PTA. The possible mechanism is related to releasing NO, oxygen radical and opioid after reperfusion. ②Adenosine do not participate in this protection, and opioid induced protection is not concerned with apoptotic pathway.