Introduction

The endocannabinoid system plays an important role in regulating the immune responses in inflammation. At present, there are no good clinical drugs for many immune liver diseases.

Methods

We explored the protective effect of the cannabinoid type II (CB2) receptor agonist AM1241 on the liver of mice with acute liver injury caused by concanavalin from the perspective of inflammation and immunity. Pathological evaluation in hepatic tissue was examined by haematoxylin and eosin (HE) staining and the levels of biochemical parameters in the serum were measured by automatic biochemical analysis. The content of inflammatory factors was measured by enzyme-linked immunosorbent assay and real-time quantitative reverse transcription polymerase chain reaction (real-time PCR). The liver apoptosis-related proteins were observed by immunohistochemistry. The expression of liver injury-related proteins was analysed by Western blot. Immune cells were isolated from the liver of mice and studied in vitro.

Results

Reduced levels of alanine transaminase and aspartate transaminase were observed in ConA-induced liver injury mice treated with AM1241, together with attenuated liver damage evidenced by H&E staining. Moreover, AM1241 inhibited the protein and gene expression levels of TNF-α, IL-6 and IFN-γ in the livers of mice. The phosphorylation levels of p38, JNK, ERK1/2, P65 and cAMP response element-binding protein (CREB) in the mouse were significantly reduced in AM1241 pretreatment, while the level of p-JNK increased. In addition, the P/T-P65 and P/T-CREB of the AM1241 pretreatment group were significantly reduced. The results of immunohistochemistry measurement are consistent with those of Western blotting. The CB2-mediated effect is through macrophage-like Kupffer cells.

Conclusion

Our study suggests that the ConA-induced liver injury model in mice is protected by CB2 agonist AM1241 by modulation of CB2 receptor-rich immune cells, for example, Kupffer cells. Reduced inflammatory responses regulate apoptosis/cell death in the liver particularly hepatocytes and other parenchymal cells.

中文翻译：

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大麻素 II 型受体激动剂 AM1241 通过丝裂原活化蛋白激酶信号通路对 ConA 诱导的小鼠肝损伤的保护作用

介绍

内源性大麻素系统在调节炎症中的免疫反应中起重要作用。目前很多免疫性肝病还没有好的临床药物。

方法

我们从炎症和免疫的角度探讨了大麻素 II 型（CB2）受体激动剂 AM1241 对伴刀豆球蛋白致急性肝损伤小鼠肝脏的保护作用。通过苏木精和伊红（HE）染色检查肝组织的病理学评价，并通过自动生化分析测量血清中生化参数的水平。采用酶联免疫吸附法和实时定量逆转录聚合酶链反应（real-time PCR）测定炎症因子含量。免疫组化观察肝细胞凋亡相关蛋白。Western blot分析肝损伤相关蛋白的表达。从小鼠肝脏中分离出免疫细胞并进行体外研究。

结果

在用 AM1241 处理的 ConA 诱导的肝损伤小鼠中观察到丙氨酸转氨酶和天冬氨酸转氨酶水平降低，同时 H&E 染色证实肝损伤减轻。此外，AM1241 抑制小鼠肝脏中 TNF-α、IL-6 和 IFN-γ 的蛋白质和基因表达水平。在 AM1241 预处理中，小鼠 p38、JNK、ERK1/2、P65 和 cAMP 反应元件结合蛋白 (CREB) 的磷酸化水平显着降低，而 p-JNK 水平升高。此外，AM1241预处理组的P/T-P65和P/T-CREB显着降低。免疫组化检测结果与Western blotting结果一致。CB2 介导的作用是通过巨噬细胞样枯否细胞。

结论

我们的研究表明，CB2 激动剂 AM1241 通过调节富含 CB2 受体的免疫细胞（例如枯否细胞）来保护 ConA 诱导的小鼠肝损伤模型。减少的炎症反应调节肝脏中的细胞凋亡/细胞死亡，特别是肝细胞和其他实质细胞。