茶多酚对去卵巢大鼠肝脏脂质代谢及JNK、Caspase-3蛋白表达的影响

目的 探讨茶多酚（tea polyphenols, TP）对去卵巢大鼠肝脏脂质代谢及JNK、Caspase-3蛋白表达的影响。 方法 60只SD雌性大鼠按体重将其随机分为假手术组（Sham）、去卵巢组（OVX），75、150、300mg/kg TP干预组（L-TP、M-TP、H-TP）及60mg/kg VE组（VE），每组10只。除Sham组外，其余各组实施双侧卵巢摘除术，术后恢复1周开始每日腹腔注射D-半乳糖100mg/kg；Sham组仅切除卵巢附近等体积脂肪组织，注射等量生理盐水。同时，L-TP、M-TP、H-TP组及VE组每日给予相应TP及VE灌胃，其余两组每日给予等体积蒸馏水灌胃，干预持续12周，并于每周记录大鼠体重。干预结束后，检测大鼠血清和肝脏TC、TG水平，HE染色观察肝组织形态学改变，Western Blot测定肝脏组织JNK、Cleaved Caspase-3蛋白的表达水平。 结果 与Sham组比，OVX组大鼠体重明显增加（P<0.05），血清TG及肝脏TC、TG水平均升高（P<0.05），肝组织内肝索结构排列紊乱，炎性细胞浸润，脂肪空泡明显可见（P<0.05），JNK、Cleaved Caspase-3蛋白表达水平增加（P<0.05）；与OVX组比，M-TP、H-TP组和VE组血清TG及肝脏TC、TG水平降低（P<0.05），脂肪空泡明显改善（P<0.05），JNK和Cleaved Caspase-3蛋白表达下调（P<0.05）；且H-TP干预能明显改善血清TG及肝脏TC、TG的水平（P<0.05）。 结论 TP干预可以降低去卵巢大鼠血清及肝脏脂质水平并下调肝细胞JNK、Caspase-3蛋白表达发挥一定的肝脏保护作用。

Effects of teapolyphenols on hepatic lipid metabolism and the expression of JNK and Caspase-3 in ovariectomized rats

Objective To investigate the effects of tea polyphenols (TP) on hepatic lipid metabolism and the expressions of JNK and Caspase-3 in ovariectomized rats. Methods A number of 60 Sprague-Dawley (SD) female rats were randomly divided into the Sham group (Sham), the ovariectomized group (OVX), 75, 150, 300 mg/kg TP intervention groups (L-TP, M-TP, H-TP) and 60 mg/kg VE group (VE). Rats were performed bilateral ovariectomy and intraperitoneal injection of 100 mg/(kg·d) D-galactose after 1 week of postoperative recovery in the OVX, L-TP, M-TP, H-TP and VE groups. The Sham group only removed the same volume of fat near the ovary, and normal saline was injected intraperitoneally. Meanwhile, 4 intervention groups were treated with TP or VE, and intragastric distilled water was administered daily to the other two groups for 12 weeks. Body weight was recorded each week. After the intervention, the levels of TC, TG in serum and liver were measured. HE staining was used to observe the pathological changes of liver. The protein expression levels of JNK and Cleaved Caspase-3 in liver of rats were detected by Western Blot. Results Compared with the Sham group, the weight of rats, the level of TC in liver and the level of TG both in serum and liver increased in the OVX group. Together with the increased JNK and Cleaved Caspase-3 expressions in the liver, disordered arrangement of hepatic cord structure, inflammatory cell infiltration and hepatocellular steatosis were found in the OVX group. In contrast to the OVX group, both the level of TC, TG of liver and TG of serum decreased. Additionally, hepatocellular steatosis decreased and JNK and Cleaved Caspase-3 expressions of liver were decreased in the M-TP, H-TP and VE groups. Interestingly, the levels of serum TG and liver TC and TG were markedly decreased in 300 mg/kg TP treatment group rather than the VE treatment. Conclusion TP intervention may play a role in protecting the liver by decreasing the level of serum and liver lipid and down-regulating the expression of JNK and Caspase-3 of the hepatocyte.