Matrine induces apoptosis in angiotensin II-stimulated hyperplasia of cardiac fibroblasts: effects on Bcl-2/Bax expression and caspase-3 activation.

The present study was designed to assess the effect of matrine, an active component of Chinese traditional medicine, on angiotensin II (Ang II)-induced hyperplastic growth of cardiac fibroblasts in vitro. Cardiac fibroblasts were prepared from hearts of neonatal Kunming mice by collagenase disruption. Cultured cardiac fibroblasts were either not treated, treated with 0.1 microM Ang II, or matrine (2.0 approximately 4.0 mM) plus Ang II for 12-72 hr. Cell morphology was monitored under an inverted phase contrast microscope. Number of cells was counted with a haemocytometer. Cell apoptosis was determined by propidium iodide/Hoechst 33342 staining and flow cytometry. The cleaved caspase-3 fragment expression, anti-apoptotic Bcl-2 and pro-apoptotic Bax protein expressions were also studied. The results show that Ang II stimulation resulted in hyperplastic growth of cardiac fibroblasts. Matrine significantly, dose and time dependently inhibited Ang II-induced cell proliferation. Matrine addition to the culture medium led to most cells being arrested in the G1 phase of the cell cycle, the fraction of cells in S phase was markedly decreased compared to control and Ang II alone groups. Cell apoptosis in matrine treatment group was markedly increased, accompanied by down-regulation in Bcl-2/Bax ratio and up-regulation in cleaved caspase-3 activity. These results suggest that matrine can induce apoptosis and thereby inhibit Ang II-induced hyperplasic growth of cardiac fibroblasts. The regulations of matrine on Bcl-2/Bax expression and caspase-3 activation may be the pro-apoptotic mechanisms involved.