Résumé
Aim To research the effects of total flavones of rhododendra(TFR)on transient receptor potential vanilloid receptor 4(TRPV4)in cerebral basilar arteries(CBA)of rats subjected to ischemia/reperfusion(IR)injury.Methods The model of total brain IR was established by four-artery occlusion(4-VO)method in rats.Arterial pressure perfusion and cell membrane potential recording methods were used for surveying the dilatation and hyperpolarization of TFR and ruthenium red(RR,an inhibitor of TRPV4)in the KCl-preconstricted CBA ex vivo in rats subjected to IR.Quantitative real-time polymerase chain reaction(qRT-PCR)and Western blot were utilized to investigate the TRPV4 mRNA and protein expressions of TFR and RR in cerebrovascular endothelial cells of CBA in vivo in rats subjected to IR.Results 11～2 700 mg·L-1 TFR significantly induced concentration-dependent hyperpolarization and dilatation in the KCl-preconstricted CBA in rats subjected to IR.TFR still produced degenerative hyperpolarization and dilatation by removal of endothelium in CBA,which was remarkably attenuated as compared with endothelium-intact group(P<0.01).After removal of NO and PGI2 vasodilatation,TFR obviously elicited the hyperpolarization and dilatation that were further decreased by RR(an inhibitor of TRPV4)in IR CBAs.TFR pretreatment apparently increased the level of TRPV4 mRNA and protein expressions in IR CBAs.These effects were restrained by RR,an inhibitor of TRPV4.Conclusions TFR could mediate endothelium-dependent and endothelium-independent effects.The endothelium-derived dilatation may be related to the increase of endothelium activity and endothelium-derived hyperpolarizing factor(EDHF)generation and release that have been promoted by TFR,and secondarily activating TRPV4,which results in Ca2+ inflow and subsequent hyperpolarization of vascular smooth muscle cell membrane and vasorelaxation.
Résumé
Aim To investigate the method of cell culture for smooth muscle cells from rat cerebral basilar artery and understand cells growth and biological characteristics.Methods The explant attached method was applied for cell culture of rat basilar artery smooth muscle cells(BASMCs).The cultured BASMCs were identified by immunocytochemical staining.The activities of cells were indicated by the dynamic changes of intracellular calcium concentration observed by RF-5 000 fluorospectro-photometer.Results BASMCs grew out of tissue blocks by 5 days,reached confluency could be subcultured after 2 weeks.Cultured cells were identified by intensely positive immunocytochemical staining to smooth muscle actin-specific.Introduction of calcium channel agonists induced significant increase in Fura-2 fluorescence ratio(F340/F380)and cells were in good condiction.Conclusion Explant attached method is simple,efficient and economic.It provides an ideal cell model for the study of pathogenesis of the cerebral vascular diseases.