小檗碱预防脂多糖性肝损伤的机制研究

目的： 观察小檗碱对脂多糖性肝损伤的防治效果及其作用机制。 方法： 将雄性昆明小鼠随机分成4组：① 对照组：用蒸馏水灌胃（0.01 mL/g），每天1次，共5 d，第5 d灌胃后1 h，腹腔注射生理盐水（0.02 mL/g）；②小檗碱组：用5 g/L中性硫酸小檗碱灌胃（0.01 mL/g），每天1次，共5 d，第5 d灌胃后1 h，腹腔注射生理盐水（0.02 mL/g）； ③ 脂多糖（LPS）组：除腹腔注射LPS（0.02 mL/g，28 mg/kg）外，其余处理同①；④小檗碱防治组：除腹腔注射LPS（0.02 mL/g，28 mg/kg）外，其余处理同②。腹腔注射后2 h和10 h去眼球取血，分别检测各组小鼠血清中TNF-α的含量以及丙氨酸氨基转移酶（ALT）和天冬氨酸氨基转移酶（AST）的活性；另于腹腔注射后24 h取肝组织标本，观察各组小鼠肝脏的组织学和超微结构的变化,同时测定肝组织MDA的含量及SOD的活性。 结果： LPS组小鼠血清ALT、AST活性明显高于对照组（P＜0.01），而小檗碱防治组小鼠血清ALT和AST活性明显低于LPS组（P＜0.05）。腹腔注射LPS后2 h，LPS组小鼠血清中TNF-α含量明显高于小檗碱防治组。组织学检查发现，LPS组小鼠肝细胞水肿、变性、坏死，肝窦充血；电镜下可见，肝细胞核溶解、部分核膜不完整，线粒体肿胀、嵴消失。小檗碱防治组小鼠肝脏的病理变化明显轻于LPS组。此外，LPS组肝脏组织中MDA的含量明显高于对照组（P＜0.01），而小檗碱防治组肝脏组织中MDA的含量低于LPS组（P＜0.05），但小檗碱防治组肝组织中SOD活性与LPS组比较无显著差异。 结论： 小檗碱可以减轻LPS引起的肝脏损伤，其作用机制可能与其抑制LPS诱导的TNF-α释放，减少肝组织脂质过氧化和保护肝细胞线粒体有关。

Mechanisms underlying the protection of berberine against liver injury induced by lipopolysaccharide in mice

AIM: To investigate the protective effects of berberine against liver injury induced by lipopolysaccharide in mice and the mechanisms underlying its protective effect. METHODS: The male mice were divided randomly into control, berberine group, LPS group and berberine treatment group. Mice were administered intragastrically with distilled water (0.01 mL/g) or 5 g/L neutral sulfate berberine (0.01 mL/g) once a day for 5 days and injected intraperitoneally with normal saline or LPS （0.02 mL/g，28 mg/kg）at 1 h after gavage on day 5. Blood was collected for determining alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, the content of tumor necrosis factors-α (TNF-α) at 10 h and 2 h after LPS or normal saline injection, respectively. Furthermore, the liver tissue was processed, and histological changes and ultrastructure in liver were observed with light and electron microscopy, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in liver were also detected. RESULTS: Both ALT and AST activities in serum in LPS group were higher than those in control and berberine treatment group. LPS increased the serum TNF-ɑ content at 2 h after injection, which was reversed by berberine pretreatment. The histological examination showed that LPS caused severe hepatic cell edema, degeneration, apoptosis and even necrosis, and ultrastructure observation demonstrated that LPS induced mitochondrial swelling, condensation and margination of chromatin, irregular nuclear envelope in hepatocytes. The above pathological changes produced by LPS were attenuated by berberine pretreatment. Moreover, MDA contents in liver tissue were higher in LPS group than control and berberine treatment group, but there were no significant difference in SOD activity between berberine treatment and LPS group. CONCLUSION: Berberine has a protective effect on LPS-induced liver injury in mice, the mechanisms may be related to its decreasing the production of TNF-α, inhibiting lipid peroxidation and protecting mitochondria.