间断低氧预适应对大鼠肝切除缺血再灌注肝脏凋亡相关蛋白Bcl-2、Bax表达的影响

Effects of intermittent hypoxic preconditioning on apoptosis-related Bcl-2 and Bax protein expression in rat liver after partial hepatectomy under ischemia-reperfusion

目的 观察术前间断低氧预适应对大鼠70％肝切术后缺血再灌注损伤肝脏凋亡相关蛋白Bcl-2和Bax表达的影响。方法 健康清洁级SD大鼠54只,用SPSS软件随机分为3组,每组18只：（1）肝切除组（PH组）,切除肝脏的左叶和中叶（约占总肝重的70％）;（2）缺血再灌注组（IR组）,即在肝门阻断下切除肝脏的左叶和中叶,肝门阻断20 min后开放血流,残余肝脏发生了缺血再灌注过程;（3）间断低氧预适应组（IHP组）,术前1周将大鼠置于氧气体积分数为10％的低氧环境中,每天1h。1周后在肝门阻断下行肝切除术（同IR组）。各组分别于术后12、24、48 h进行取材检测,用全自动生化分析仪检测血清谷丙转氨酶（ALT）、谷草转氨酶（AST）含量,采用免疫组化方法检测残余肝组织Bcl-2、Bax表达情况。结果 在术后各时间点,IR组和IHP组血清ALT和AST水平均显著高于PH组,但IHP组明显低于IR组。与IR组相比,IHP组术后各时间点肝脏Bcl-2蛋白表达显著升高,而Bax蛋白表达显著下降。差异均有统计学意义（P＜0.05）。结论 间断低氧预适应对残余肝脏缺血再灌注损伤具有保护作用,其途径可能是通过促进抗凋亡蛋白Bcl-2表达和抑制促凋亡蛋白Bax表达,来减少肝细胞凋亡。

Objective To observe the effects of intermittent hypoxic preconditioning on the expression of apoptosis-related Bcl-2 and Bax protein after 70％ hepatectomy combined with ischemia-reperfusion injury.Methods A total of fifty-four SD rats were randomly divided into three groups （n =18）.Partial hepatectomy hroup （PH Group）：Rats underwent the left and middle lobectomy of liver（70％ hepatectomy）.Ischemia reperfusion group （IR group）：The left and middle lobes of liver were resected during the occlusion of the hepatoduodenal ligament for 20 minutes.Residual liver underwent the process of ischemia-reperfusion.Intermittent hypoxia preconditioning group （IHP group）：rats were exposed to hypoxic environment of 10％ oxygen for 1 h/d.After 7 consecutive days,the left and middle lobes of liver were resected under the portal triad clamping.At 12,24 and 48 hours after the operation,the rats were killed and detected.The serum levels of ALT and AST were determined by automatic biochemical analyzer.The expression of Bcl-2 and Bax protein in liver tissue were measured by immunohistochemistry.Results At each time point after surgery,the serum levels of ALT and AST in IR group and IHP group were higher than that of PH group,and IHP group were lower than in IR group.Compared with IR group,the expression of Bcl2 protein significantly increased and Bax protein expression significantly decreased in IHP group.All these differences were statistically significant （P ＜ 0.05）.Conclusions Intermittent hypoxic preconditioning might protect residual liver against ischemia reperfusion injury,through increasing the expression of Bcl-2 protein and reducing the expression of Bcl-2 protein to decrease liver cell apoptosis.