大麻素受体2介导的N-花生四烯酸氨基乙醇对肝星状细胞增殖和活化的影响

目的 观察内源性大麻素N-花生四烯酸氨基乙醇(AEA)及大麻素受体(CBR)2对肝星状细胞(HSC)增殖活化的影响,以探讨内源性大麻素及其受体系统在肝纤维化发展中的作用.方法 采用免疫荧光观察血小板衍生生长因子(PDGF)刺激前后HSC中CBR1和CBR2的表达.Western blot、PCR法观察不同浓度AEA及CBR2拮抗剂AM630对PDGF刺激下HSC增殖及活化的影响,同时用四甲基偶氮唑盐、流式细胞仪分析AEA对HSC活力及凋亡的影响.结果 HSC中CBR2的表达较CBR1高(F=116.797,P<0.01),且PDGF刺激后CBR2的表达明显增强(F=7.878,P<0.05).AEA可剂量依赖地抑制HSC的增殖,在浓度为10,20、50μmol/L时抑制率分别为7.12%±0.34%、12.52%±0.78%、80.13%±1.57%,差异有统计学意义(F=533.41,P<0.01);但对HSC凋亡的影响不明显.同时AEA可抑制HSC的活化指标α-平滑肌肌动蛋白、转化生长因子β1、Ⅰ型胶原、Ⅲ型胶原及基质金属蛋白酶抑制因子等的表达,但这种抑制作用在给予CBR2拮抗剂AM630后明显减弱,差异有统计学意义(P<0.05).结论 CBR2在AEA引起的HSC增殖及活化抑制中起关键作用,AEA和CBR2可望成为肝纤维治疗的新靶点.

Effects of anandamide on the activation and proliferation of hepatic stellate cells through cannabinoid-2 receptors

OBJECTIVE: To study the effects of endogenous cannanbinoid anandamide (AEA) and its putative endocannabinoid receptors (CBR) on the activation and proliferation of hepatic stellate cells (HSC) and to study the role played by AEA during liver fibrosis. METHODS: By using immunofluorescence and cell culture, the expression of CBR 1 and 2 in the PDGF-stimulated HSCs was investigated. By using PCR and Western-blot, the effects of 10, 20mumol/L AEA and CBR2 antagonist AM630 on the cultured and activated HSC were observed. Methyl thiazolyl tetrazolium and flow cytometry were used to investigate whether AEA induces growth inhibition or apoptsis in the activated HSCs. RESULTS: Both CBR1 and CBR2 receptors were detectable in cultured HSCs with a higher level of CBR2 than CBR1 (F = 116.797, P less than 0.01). When HSCs were stimulated by PDGF, the expression of CBR2 receptors was significantly enhanced (F = 7.878, P less than 0.05). HSC proliferation was dose-dependently inhibited by 10, 20, and 50micromol/L AEA, with the rates of 7.12%+/-0.34%, 12.52%+/-0.78%, 80.13%+/-1.57% respectively (F = 533.41, P less than 0.01). However, it did not induce apoptosis, but necrosis. The expressions of alpha-SMA, TGFb1, a1(I), a1(III) and TIMP-1 were significantly suppressed by 20micromol/L AEA, but CBR2 antagonist AM630 reversed this suppressor action of AEA. CONCLUSIONS: AEA may inhibit activation and proliferation of HSCs; CBR2 receptors mediate AEA-induced inhibitory action on the activation of HSCs. This CBR2 receptor-mediated action and AEA on HSCs could be used as a therapeutic target against liver fibrosis.