二氮嗪强化Celsior液可安全延长供心低温保存时限

目的 评价二氮嗪(Diazoxide,DE)强化Celsior液对移植鼠供心长时程(10 h)低温保存的有效性,并探讨其可能作用机制.方法 采用改良Heron法大鼠颈部异位心脏移植模型.SD近亲大鼠随机分为3组,(1)对照组:单纯Celsior液保存鼠心;(2)实验组:30umol/L DE+Celsior液保存鼠心;(3)拮抗组:100~enol/L 5-lid+30tnnol/LDE+C~ior液保存鼠心5h;前两组根据保存时间不同分为5、10h组.观察移植心脏复跳情况,并分别于复跳后5 trfin、l周、3个月时留取标本,检测心肌MDA含量、SOD活性、心肌pfl'p酶、TNF-a、F~/FasL、Caspase-3、AI等指标以及超微结构检查.结果 (1)相同保存时间,实验组与对照组比较,术后5 rrfin和l周各指标均有明显优越性;术后3个月时各指标亦较佳,心肌MDA含量低下、SOD和N且'.K+ATP 酶活性高及FasL、TNF-a基因表达低差异有统计学意义;(2)孓HD消除了实验组中添加DE的优势作用;(3)实验10 h组与对照5 h组比较,各指标均稍有优越性;(4)DE各组和Cetsior 5h组心肌超微结构保护相对较佳:肌纤维排列整齐,肌节清,线粒体肿胀不明显,嵴结构较为清楚;celsior 10h组心肌肌纤维疏松,部分区域肌丝肌节溶解,线粒体肿胀较明显,嵴模糊.结论 DE强化Celsior液长时程冷保存鼠供心可较国际公认4-6h延长至1Oh,仍安全有效.其主要原因可能与DE介导mito-KATrC开放,早期阶段抑制氧化应激引起的细胞凋亡、阻止细胞内钙超载、降低凋亡相关基因表达等对抗心肌缺血再灌注损伤的心肌保护作用有关.

Long-term hypothermic preservation of rat hearts with diazoxide-containing celsior solution

Objecltve To assess the effectiveness of diaxoxide-containing Celsior cardioplegia solution for long-term preservation of the Rat Hearts in vitro,and to study the potential mechanisms of diazoxide,an ATP-sensitive mitochondrial potassium channel opener in reducing the ischemia-reperfusion injury.Methods The modified Heron's technique for heterotopic cervical heart transplanation in rat models was used.Before transplantation,SD rats were randomized into control groups ,in which the donor rats'hearts were stored in Celsior cardioplegia solution at 4 C for 5 or 10 hours,experimental groups,in whieh diazoxide(30yumol/L)was to Celsior solurtion for 5 or 10hours,and a group of antagonism ,in which 5-hydroxydecanoate(5-HD),a mito-KATPC inhibitor,was added to the solution(in 100 umol/L) used in the experimental groups for 5 hours.Samples of the miyocardium were collected at 5 min,1 week ad 3 months after heart transplantation and were messured for the level of melondialdehyde(MDA),the activities of superoxide dismutase(SOD),Na+-AT- Pase and Ca2+-ATPase.The gene expresssion of TNF-a,Fas/FasL and Caspase-3 was analyzed.Apoplotic cardiomyocytes were detected by TdT-mediated dUTP nick end Labeling(TUNEL)technique.The myocardial ultrastructre was also observed.Results The experi-mental groups were much superior to the control groups in the measurements at 5 minutes and 1 week after beart transplantation,for whichthe donor rats 'bearts were preserved for the same period.The superioroties were maintained at 3 months,The level of MDA was decreased significantly,the netivites pf SOD and Na+-k+-ATPase were enhanced,gene expression of FasL and Tnf-a was reduced with dlmmide.The effectss of diazoxide were eliminated by 5-HD.Modeet si[eropmotoes were observed in one experimental group in which the donor rate'hefts were preserved for 10 hours ,as compared with one control group in which the donor rats'hearts were preserved for 5 houm.Histologically,the myo cardial ultrastructure was preserved relatively well in teh experinental groups and in the 5-hourpresera-tion control group.Conclusion Diazoxide-containing Celsior solution provides longer protection for the donr rats'hearts than well-es-tablished period of 4 to 6 hours.These findings indicate that the mechanisme for diazoxide to alleviate ischemoia-reperfusion injury to the rat myocardium may be associated with its roles in the myocardal protection,which involving early opening of mito-KatpC, a process providing protection for mitochondrial structure and function,enrly in-hilaition of apoptosis induced by axidative stress,prohibition of cal-cimn overloadinthe cells.reduction of the expression 0f apoptosis-related genes.The heartsmay be preserved safely and effectovely in dimoxide-containing Celsior cardioplegia solution for 10 hours.