[Effects of anandamide on the activation and proliferation of hepatic stellate cells through cannabinoid-2 receptors].
OBJECTIVE
To study the effects of endogenous cannabinoid 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 apoptosis 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.
Liu
Hong-yan
HY
Institute of Liver Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Yang
Qiao
Q
Duan
Rui-xian
RX
Zhang
Yao-wen
YW
Tang
Wang-xian
WX
D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology*; D063385:Cannabinoid Receptor Modulators / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D063388:Endocannabinoids; D055166:Hepatic Stellate Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D053284:Polyunsaturated Alkamides / Q000494:pharmacology*; D051381:Rats; D043885:Receptor, Cannabinoid, CB2 / Q000378:metabolism*
D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D007211:Indoles; D053284:Polyunsaturated Alkamides; D043885:Receptor, Cannabinoid, CB2; C094023:iodopravadoline; C078814:anandamide