常温下缺血预处理对肝细胞凋亡调节基因表达影响的实验研究

目的 探讨常温下大鼠肝脏缺血预处理对细胞凋亡调节基因C-jun和Bcl-X_L的表达及其对肝细胞的保护作用。方法 将30只Wistar大鼠随机分成假手术组(S组,10只)、缺血再灌注组(IR组,10只)、缺血预处理组(IP组,10只)。S组在游离肝蒂后、IR组和IP组在再灌30 min后0、1、3、6、20 h点采集肝组织标本切片行肝细胞凋亡,C-jun和BcI-X_L基因表达及形态学改变等检测。各组均在3、6、20 h点采集血标本检测肝损害标记酶(ALT、AST、LDH)。结果 ALT、AST及LDH值各时间点IR组和IP组均明显高于S组(P<0.01),IP组明显低于IR组(P<0.01)。IR组和IP组与S组比较,细胞凋亡指数(AI)有显著性增加(P<0.01),IP组与IR组比较,AI明显减少(P<0.01)。C-jun基因在S组和IP组各时间点表达不明显;在IR组表达明显,3h点达高峰,并持续至6h点。Bcl-X_L基因在S组、IR组各时间点表达不明显,在IP组3、6、20h点表达明显(P<0.05或P<0.01)。形态学研究显示,IR组有肝组织大片坏死及不可逆超微结构损害;IP组未见明显肝细胞坏死,且超微结构损害为可逆性。结论 ①缺血预处理通过调节肝细胞凋亡调节基因C-jun和Bcl-X_L的表达,发挥其对大鼠常温下肝脏缺血再灌注损伤的保护作用;②IR损伤可能通过激活凋亡诱导基因C-jun表达而促发大鼠肝细胞的过度凋亡;③IP可能通

Effects of normothermic liver ischemic preconditioning on expression of apoptosis-regulating genes C-jun and Bcl-XL in rats

Objective To explore the expression of apoptosis-regulating genes C-jun and Bcl-XI, after normothermic liver ischemic preconditioning and its protective effects on hepatocytes in rats. Methods Wistar rats were randomized into sham-operated group (S group, n=10), ischemia/reper-fusion group (IR group, n=10) and ischemic preconditioning group (IP group, n=10). After dissection of the hepatoduodenal ligament in S group and 30-min reperfusion in IR group and IP group, the samples of liver tissue were taken from all rats for determination of hepatocellular apoptosis, expression of C-jun mRNA and Bel-XL mRNA and liver morphological changes in 0, 1, 3, 6 and 30 h. Meanwhile, samples of venous blood were collected in 3, 6 and 20 h for detection of ALT, AST and LDH. Results The levels of ALT, AST and LDH were significantly higher in IR group and IP group than in S group (P<0. 01). Hepatocellular apoptosis was rarely seen in S group. However, the apoptotic index (AI) of hepatocytes was markedly increased in both IR group and IP group (P<0. 01). It was remarkably higher in IR group than in IP group (P<0. 01). The expression of C-jun mRNA was significantly enhanced in IR group as compared with IP group and S group (P<0. 05 or 0. 01), but no significant difference in the expression was found between IP group and S group at all time phases (P> 0. 05). The expression of Bcl-XL mRNA was not markedly different between IR group and S group in all time phases (P>0. 05). It was remarkably different between IR group and IP group in 3, 6 and 20 h after the procedures (P<0. 05 or 0. 01). Patchy necrosis of hepatocytes could be seen in IR group under the microscope and the ultrastructural changes were irreversible. Meanwhile, no hepatocellular necrosis occurred and the ultrastructural changes reversible in IP group. Conclusions (1) Ischemic preconditioning can protect the rat liver from normothermic ischemic reperfusion injury by modulation of the expression of apoptosis-regulating genes C-jun and Bel-XL. (2) IR injury may activate the apop-tosis of hepatocytes by increasing the expression of apoptosis-inducing gene C-jua (3) IP may prohibit the apoptosis of hepatocytes by increasing the expression of apoptosis-inhibitory gene Bcl-XL.