大鼠无心跳供体热缺血损伤后供肝组织学与超微结构的动态变化

Histological and ultrastructural alterations of liver graft undergoing warm ischemia injury from non-heart-beating donor in rats

目的动态观察移植肝热缺血损伤后组织学与超微结构的变化特点,预测无心跳供体(NHBD)中供肝耐受热缺血的安全时限。方法实验动物按供肝热缺血时间分别为0、10、15、20、30、45、60min,随机分为7组。按各组条件分别作原位肝移植,动态观察单纯热缺血期和肝移植术后6 h、24 h、48 h各组移植肝组织学、组织化学和超微结构变化规律。结果NHBD的供肝不仅发生热缺血阶段缺血缺氧造成的损伤,在移植肝复流后,也存在再灌注损伤,且再灌注期肝组织损伤的程度与热缺血时间长短有密切关系。热缺血30 min以前,移植肝仅出现组织细胞的变性,未见明显坏死。45 min组,肝组织可见小灶状的坏死,在小叶中央区首先发生。60 min组,肝细胞坏死的范围扩大,呈片状或弥漫性分布;肝窦内皮细胞明显肿胀呈泡状或气球状,肝血窦阻塞,呈微循环障碍。结论大鼠供肝经受30 min以内热缺血损伤,肝组织损伤处在可复性阶段。热缺血60 min以后,呈现不可逆性的形态学改变。

Objective To investigate the histological and uhrastructural characteristics of liver graft after different warm ischemia time （WIT） in rats. Methods According to WIT, rats were randomized into 7 groups, with WIT of 0, 10, 15, 20, 30, 45, 60 minutes respectively. All specimens were investigated by light, electron microscopy, and histochemistry stain. 6, 24, and 48 hours after orthotopic liver transplantation（OLTx） , the graft morphology was observed. Results The donor liver from non-heartbeating donors（NHBD） underwent ischemia injury both in the warm ischemia period and in the reperfusion period. Morphological changes were positively related to warm ischemia time in a time-dependent manner during the reperfusion period. There was a histocytic degeneration of different degree within 30 minutes warm ischemia. Although becoming more severe with the prolongation of warm ischemia time within this period, there was no obvious hepatocyte necrosis in any specimens. In WIT 45 min group, small focal necrosis occurred which was found in central area of hepatic lobule first. In 60 min group, patchy or diffused necrosis was observed and the area was gradually extended, while hepatic sinusoid endothelial cell obviously swelled to be bleb or balloonlike, hepatic sinusoid was obstructed and microcirculation was in disorder. Conclusion Rat liver graft undergoing warm ischemia injury is on the reversible stage within 30 minutes warm ischemia time by histological, histochemistry and uhrastructural dynamic observation. 45 min is a critical point of rat liver graft to endure warm ischemia injury, and when WIT was over 60 min, the damage is irreversible.