合欢皮乙醇提取物通过调控NF-κB通路减轻四氯化碳诱导的小鼠急性肝损伤

Ethanol extract from Cortex Albiziae attenuates mouse acute liver injury induced by carbon tetrachloride via modulation of NF-κB pathway

目的:研究合欢皮乙醇提取物对急性肝损伤的作用,并对其可能的作用机制进行初步探讨。方法:釆用25%四氯化碳(橄榄油助溶)单次腹腔注射诱导小鼠急性肝损伤模型,筛选合欢皮乙醇提取物抗急性肝损伤的活性部位。通过HE染色观察肝组织形态结构的病理变化,检测肝组织中总超氧化物歧化酶(T-SOD)活性和丙二醛(MDA)含量,ELISA检测血清中白细胞介素6(IL-6)和肿瘤坏死因子α(TNF-α)水平,Western blot检测各组小鼠肝细胞中NF-κB p65、Bcl-2和Bax的蛋白表达水平。结果:与model组比较,合欢皮乙醇提取物正丁醇相低剂量(AB-L,4 mg·kg^-1·d^-1)组和高剂量(AB-H,8 mg·kg^-1·d^-1)组血清中AST水平和ALT水平显著降低。HE染色病理学观察可见肝细胞坏死范围、程度和炎细胞浸润较model组明显减轻。与model组比较,AB-H组和AB-L组小鼠血清中的TNF-α和IL-6水平明显下降,小鼠肝细胞核中NF-κB p65的蛋白表达水平显著降低(P<0.05)。与model组比较,AB-H组和AB-L组的肝组织中Bax蛋白表达水平降低,Bcl-2蛋白表达水平升高,Bcl-2/Bax比值升高(P<0.05)。结论:合欢皮乙醇提取物正丁醇相可能通过减少NF-κB p65的活化而抑制IL-6和TNF-α炎性细胞因子的过度释放,以及调控Bcl-2和Bax蛋白的表达减轻肝细胞的凋亡,从而发挥对肝脏的保护作用。

AIM: To investigate the protective effect of ethanol extract from Cortex Albiziae on acute liver injury, and to explore its possible mechanism. METHODS: Acute liver injury in mice was induced by single intraperitoneal injection of 25% carbon tetrachloride(olive oil solubilization). The effective parts of ethanol extract from Cortex Albizziae against acute liver injury were screened. The pathological changes of the liver tissues were examined by pathological sections with HE staining. The activity of total superoxide dismutase(T-SOD) and the content of malondialdehyde(MDA) of the liver tissues were detected, the serum levels of interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) were mea-sured by ELISA, and the protein expression levels of NF-κB p65, Bcl-2 and Bax in the liver cells of the mice in each group were determined by Western blot. RESULTS: Compared with model group, the serum levels of AST and ALT in low-dose n-butanol phase of ethanol extract from Cortex Albiziae(AB-L, 4 mg·kg^-1·d^-1) group and high-dose n-butanol phase of ethanol extract from Cortex Albiziae(AB-H, 8 mg·kg^-1·d^-1) group were significantly decreased. The necrosis extent and degree of the hepatocytes and infiltration of inflammatory cells were significantly lower than that in model group. Compared with model group, the serum levels of TNF-α and IL-6 in AB-H group and AB-L group were significantly decreased(P<0.05). The protein level of NF-κB p65 in the nuclei of mouse liver cells in AB-H group and AB-L group were also decreased significantly(P<0.05). Compared with model group, the protein expression of Bax was decreased, the protein expression of Bcl-2 was increased, and the Bcl-2/Bax ratio was increased in AB-L group and AB-H group. CONCLUSION: The n-butanol phase of ethanol extract from Cortex Albiziae may protect the liver by reducing the activation of NF-κB p65, inhibiting the excessive release of inflammatory cytokines IL-6 and TNF-α, and decreasing hepatocyte apoptosis via regulating Bcl-2 and Bax expression.