Negative inotropic effect of basic fibroblast growth factor on adult rat cardiac myocyte

Background: Basic fibroblast growth factor (bFGF) is highly expressed in the myocardium in some cardiac disorders, such as ischemia-reperfusion and cardiac allograft rejection. However whether bFGF has any effects on myocardial contract on is unknown. Methods arm Results: We examined the effects of bFGF on myocardial contractility using isolated adult rat cardiac myocyte preparations. bFGF exerted a direct negative inotropic effect that was concentration and time dependent. The pretreatment of myocytes with a neutralizing anti-bFGF antibody (100 ng/mL) abolished the negative inotropic effects of bFGF (100 ng/mL). Platelet-derived growth factor (12.5 ng/mL) and transforming growth factor-β (1 ng/mL) did not exert such effects, which indicated that bFGF-induced negative inotropism was considered to be specific for this growth factor. bFGF decreased the peak intracellular Ca²⁺ transient by 46% during systole. The enhanced production of nitric oxide was unlikely to be responsible for the bFGF-induced negative inotropic effect. Conclusions: bFGF, primarily a potent growth promoter, produced acute negative inotropic effects in the adult cardiac myocyte that could have resulted from alterations in intracellular Ca²⁺ homeostasis. The negative inotropic effect of bFGF may contribute to myocardial dysfunction associated with ischemia-reperfusion injury and heart transplant rejection.