齐墩果酸预先给药对大鼠肝脏缺血再灌注损伤的影响

目的 探讨齐墩果酸预先给药对大鼠肝脏缺血再灌注损伤的影响.方法 清洁级健康雄性SD大鼠128只,体重230～250 g,随机分为4组(n=32):假手术组(S组)、缺血再灌注组(IR组)、羧甲基纤维素钠组(CMC组)和齐墩果酸预处理组(OA组).OA组胃内灌注齐墩果酸混悬液100 mg/kg,CMC组以相同容积的0.5%羧甲基纤维素钠溶液、S组与IR组以相同容积的饮用水替代,每天1次,连续7 d,第8天时IR组、CMC组和OA组采用阻断门静脉及肝动脉分支60 min后再灌注的方法制备肝脏缺血再灌注模型,S组仅分离胆管及门静脉、肝动脉分支.于再灌注即刻、3、6和12 h时取下腔静脉血样,测定血清ALT活性;取左肝中叶组织,测定SOD活性、MDA和谷胱甘肽(GSH)含量和磷酸化磷脂酰肌醇-3激酶(p-PI3K)、蛋白质丝氨酸苏氨酸激酶(Akt)、p-Akt、Bcl-2、Bax、p-Bad和Bad的表达水平,观察肝组织病理学结果.结果 与S组比较,IR组、CMC组和OA组再灌注期间血清ALT活性和肝组织MDA含量升高,肝组织SOD活性和GSH含量降低,p-PI3K、p-Akt、Bax、Bad、p-Bad表达上调,Bcl-2表达下调(P＜0.05);与IR组比较,OA组再灌注期间血清ALT活性和肝组织MDA含量降低,肝组织SOD活性和GSH含量升高,p-PIK、p-Akt、Bcl-2和p-Bad表达上调,Bad和Bax表达下调(P＜0.05),CMC组上述指标差异无统计学意义(P＞0.05);与CMC组比较,OA组再灌注期间血清ALT活性和肝组织MDA含量降低,肝组织SOD活性和GSH含量升高,p-PI3K、p-Akt、Bcl-2和p-Bad表达上调,Bad和Bax表达下调(P＜0.05).OA组肝组织病理学损伤较IR组减轻.结论 齐墩果酸预先给药可减轻大鼠肝脏缺血再灌注损伤,其机制可能与激活PI3K/Akt信号通路,抑制细胞凋亡有关.

Effect of oleanolic acid pretreatment on hepatic ischemia-reperfusion injury in rats

Objective To investigate the effect of oleanolic acid pretreatment on hepatic ischemiareperfusion (I/R) injury in rats. Methods One hundred and twenty-eight male SD rats weighing 230-250 g were randomly divided into 4 groups (n = 32 each): sham operation group (group S), I/R group, 0.5% sodium carboxymethyl cellulose group (group CMC) and oleanolic acid preconditioning (group OA). Partial liver ischemia was produced by clamping hepatic portal vein and hepatic arteries for 60 min with atraumatic mini-clamp, followed by 12 h of reperfusion in group I/R, CMC and OA. Oleanolic acid suspension 100 mg/kg was infused intragastrically in group OA, while the equal volume of 0.5% CMC-Na (in group CMC) and drinking water (in group S and I/R) was infused intragastrically instead once a day for 7 days, and then hepatic I/R was performed at day 8. The left liver was removed and blood sample was taken from inferior vena cava at 0, 3, 6 and 12 h ofreperfusion for determination of serum alanine amino transferase (ALT) activity, superoxide dismutase (SOD)activity, malondialdehyde (MDA) and glutathione (GSH) content, and expression of phospho-phosphatidylinositol3-kinase (p-PI3K), Akt, p-Akt, Bcl-2, Bax, p-Bad and Bad in the liver, and microscopic examination. Results Serum ALT activity and MDA content in the liver were significantly increased, SOD activity and GSH content in the liver were significantly decreased, expression of p-PI3K, p-Akt, Bax, Bad and p-Bad was up-regulated, and Bcl-2 expression was down-regulated during reperfusion in group I/R, CMC and OA as compared with group S (P ＜0.05). Compared with group I/R, serum ALT activity and MDA content in the liver were significantly decreased, SOD activity and GSH content in the liver were significantly increased, expression of p-PI3K, p-Akt,Bcl-2 and p-Bad was up-regulated, and expression of Bad and Bax was down-regulated during reperfusion in group OA (P ＜ 0.05), but no significant change was found in the indexes mentioned above in group CMC (P ＞ 0.05).Serum ALT activity and MDA content in the liver were significantly lower, SOD activity and GSH content in the liver were significantly higher, expression of p-PI3K, p-Akt, Bcl-2 and p-Bad was significantly higher, and expression of Bad and Bax was significantly lower during reperfusion in group OA than in group CMC (P ＜ 0.05).The pathological changes in the liver were milder in group OA than in group I/R. Conclusion Oleanolic acid pretreatment can alleviate hepatic I/R injury by activating PI3K/Akt signaling pathway and inhibiting apoptosis.