银杏叶提取物EGb761对大鼠肝缺血/再灌注损伤的保护作用

Ginkgo biloba extract(EGb761)protects against hepatic ischemia/reperfusion injury in rats

目的探讨银杏叶提取物(Ginkgo biloba extract,EGb761)对大鼠肝缺血/再灌注(ischemia/reperfusion,I/R)损伤的保护作用及可能机制。方法雄性SD大鼠24只,按照随机数字表法分为4组(每组6只):假手术组(Sham组)、缺血/再灌注组(I/R组)、银杏叶提取物EGb761组(EGb组)和银杏叶提取物EGb761+丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)激动剂p79350组(EGb+p组)。Sham组大鼠仅游离肝门处血管;I/R组大鼠采用夹闭肝左叶、中叶脉管共干30 min制备70%肝I/R损伤模型;EGb组大鼠建模前30 min静脉注射EGb76150 mg/kg;EGb+p组大鼠建模前5 d连续静脉注射20%p79350溶液0.1 ml/d,其余操作同EGb761组。再灌注6 h时,取血后处死大鼠,ELISA法检测肝功能指标ALT、AST和谷氨酰转肽酶(γ-glutamyl transpeptadase,GGT),TUNEL法观察细胞凋亡情况,留取肝组织采用Western blot法检测p38 MAPK表达水平。结果与Sham组比较,I/R组、EGb组和EGb+p组大鼠血清ALT、AST和GGT浓度明显升高(P<0.05),细胞凋亡率增加(P<0.05),p38 MAPK表达增加(P<0.05)。与I/R组比较,EGb组大鼠血清ALT、AST和GGT浓度明显降低(P<0.05),细胞凋亡率降低(P<0.05),p38 MAPK表达降低(P<0.05);EGb+p组各指标与I/R组比较差异无统计学意义(P>0.05)。结论EGb761对肝I/R损伤具有保护作用,其机制可能与抑制肝p38 MAPK表达有关。

Objective To investigate the protective effects of Ginkgo biloba extract(EGb761)on hepatic ischemia/reperfusion(I/R)injury in rats and possible mechanisms.Methods According to the random number table method,24 male SD rats were divided into four groups(n=6):a Sham group,an I/R group,an EGb761(EGb)group and an EGb761+mitogen-activated protein kinase(MAPK)agonist p79350(EGb+p)group.Rats in the Sham group were dissected the porta without ligation alone;those in the I/R group were used to establish a model of 70%hepatic I/R through clamping the left and middle hepatic vein vessels for 30 min;those in the EGb group were intravenously injected with 50 mg/kg EGb76130 min before modeling;and those in the EGb+p group were intravenously injected with 20%p79350 solution at 0.1 ml/d for five consecutive day before modeling,in addition to the same treatment in the EGb group.After reperfusion for six hours,the rats were sacrificed and blood samples were collected.The levels of hepatic function indexes such as alanine aminotransferase(ALT),aspartate aminotransferase(AST)andγ-glutamyl transpeptidase(GGT)were detected by enzyme-linked immunosorbent assay(ELISA).The apoptosis of hepatic cells was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling(TUNEL)assay.The expression of p38 MAPK was detected by Western blot.Results Compared with the Sham group,the I/R group,the EGb group and the EGb+p group showed remarkable increases in the levels of ALT,AST and GGT(P<0.05);in the apoptosis rate(P<0.05)and p38 MAPK expression(P<0.05).Compared with the I/R group,the EGb group produced remarkable decreases in the levels of ALT,AST and GGT(P<0.05);in the apoptosis rate(P<0.05)and p38 MAPK expression(P<0.05).There was no significant difference as to the above indicators between the EGb+p group and the I/R group(P>0.05).Conclusions EGb761 has protective effects on hepatic I/R injury,which may be related to inhibiting the expression of p38 MAPK in the liver.