OBJECTIVESTo investigate the effects of norepinephrine (NE) on the proliferation and apoptosis of hepatic stellate cells (HSCs).

METHODSCultured HSCs were used in 6 groups: (1) a control group; (2) a NE group; (3) a phentolamine plus propranolol group; (4) a phentolamine (an alpha-AR antagonist) group; (5) a CGP20712A (a beta1-AR antagonist) group; and (6) a ICI118551(a beta2-AR antagonist) group. After NE and the antagonists of adrenoceptor subtypes were administered to the cultured HSCs, MTT assay was used to evaluate the cell proliferation at 24 h, 48 h, and 72 h. Terminal deoxyribonucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) assay and flow cytometry were used to detect cell apoptosis. An inverted microscope was used to observe the morphological changes of HSCs.

RESULTS(1) MTT assay indicated that NE significantly induced HSCs proliferation in a time-dependent manner, which were reduced by antagonist of alpha-AR, beta1-AR and beta2-AR. (2) At 24 h after HSCs exposure to NE, apoptosis rates decreased significantly compared with that of the control group (6.60%+/-3.05% vs 12.60%+/-4.76%). In the antagonists of adrenoceptor subtypes groups, especially of a and beta2 adrenoceptor subtypes, the apoptosis was less. (3) Apoptosis rate of the NE group was significantly lower than that of the control group (2.29%+/-0.22% vs 3.06%+/-0.57%). In the antagonists of alpha and b2 adrenoceptor groups the apoptosis was less. (4) No obvious morphological changes of HSCs were found after administration of NE.

CONCLUSIONSSympathetic neurotransmitter NE can induce proliferation and inhibit apoptosis of the cultured HSCs.