重复持续性＋Gz暴露对大鼠肝组织的损伤及机制研究

Damage of rat liver tissue caused by repeated and sustained +Gz exposure and the mechanism thereof

目的探讨不同正加速度(+Gz)对大鼠肝脏组织的损伤作用及其可能的机制。方法健康成年雄性Wistar大鼠24只,随机分为对照组及+2Gz、+6Gz、+10Gz组(n=6)。对照组固定于离心机转臂上,俯卧位,头向轴心,5min;+2Gz组、+6Gz组、+10Gz组固定方法同对照组,+Gz增长率1G/s,峰值时间3min,间隔30min,重复5次。+Gz暴露结束后30min处死大鼠,HE染色观察肝组织形态学变化,荧光实时定量PCR检测肝组织c-jun基因mRNA的表达,Western blotting检测肝组织p-c-Jun、c-Jun、p-JNK及JNK蛋白的表达,并测定血清天冬氨酸转氨酶(AST)和丙氨酸转氨酶(ALT)水平。结果与对照组及+2Gz组比较,+6Gz组、+10Gz组血清ALT和AST水平明显升高,且+10Gz组明显高于+6Gz组(P<0.05)。与对照组及+2Gz组比较,+6Gz组、+10Gz组c-Jun mRNA及c-Jun、p-c-Jun、p-JNK蛋白表达明显升高,且+10Gz组明显高于+6Gz组(P<0.05)。与对照组比较,其他各组JNK蛋白表达无变化(P>0.05)。HE染色显示,+6Gz、+10Gz组肝细胞排列紊乱,形态不规则,细胞间隙不清晰,空泡样改变,且+10Gz组较+6Gz组更为显著。结论重复持续性+Gz可导致肝脏细胞损伤,肝组织中c-Jun/p-c-Jun以及p-JNK表达增强,JNK/c-Jun信号通路可能在其中起重要作用。

Objective To explore the mechanisms of positive acceleration （＋Gz） on the damage of rat liver tissue and the effect of ＋Gz on the expression of JNK/c-Jun in liver cells, Methods Twenty four male Wistar rats were randomly divided into 4 groups （n=6）： control, ＋2Gz, ＋6Gz and ＋10Gz group. With prone position, the rats in control group were fixed to the turning arm of centrifuge with head towards the axis for 5 minutes. The fixation method in ＋2Gz, ＋6Gz and ＋10Gz group was the same as in the control group. The increase rate of acceleration was 1G/s with a peak-time of 3 minutes, and each ＋Gz exposure repeated S times with an interval of 30 minutes. HE staining was used to observe the morphological changes of liver tissue, fluorescence real-time quantitative PCR to detect the expression of hepatic c-Jun mRNA, and Western blotting to detect the hepatic protein expression of p-c-Jun, c-Jun, p-JNK and JNK. Plasma aspartate aminotransferase （AST） and alanine aminotransferase （ALT） were determined. Results The levels of serum ALT and AST increased significantly in ＋6Gz and, especially, the ＋ 10Gz group than in control group and ＋2Gz group （P〈0.05）. The same situation also existed in the increase of c-Jun mRNA expression （P〈0.05）. Hepatic c-jun and p-c-Jun （c-Jun activated form） protein expression increased with the increase of G value. Compared with control group, no change was found in JNK protein expression in the other three groups, but the expression of p-JNK （activated form of JNK） increased in ＋6Gz and ＋10Gz groups （P〈0.05）. HE staining showed the disorganized liver cells with irregular shapes, the unclear cell gap and the vacuolar changes in ＋6Gz and ＋10Gz groups. Conclusions Repeated and sustained ＋Gz may cause enhanced expression of c-Jun/ p-c-Jun and p-JNK in hepatic cells.JNK/c-Jun signaling pathway may play an important role in the process of hepatic stress injury.