Fibroblast growth factor-8 inhibits oxidative stress-induced apoptosis in H9c2 cells

Fibroblast growth factors (FGFs) comprise a large family of signaling molecules that involve cell patterning, mobilization, differentiation, and proliferation. Various FGFs, including FGF-1, FGF-2, and FGF-5, have been shown to play a role in cytoprotection during adverse cardiac events; however, whether FGF-8 is a cytoprotective remains unclear. The current study was designed to evaluate the effect of FGF-8 treatment on oxidative stress-induced apoptosis in H9c2 cells. Cells were divided into three groups: control, H₂O₂ (400 µm H₂O₂), and H₂O₂ + FGF-8 (4 ng/ml FGF-8). Our results suggest apoptosis was significantly (p < 0.05) enhanced in the H₂O₂ group relative to control. Moreover, a significant (p < 0.05) decline in apoptosis was observed in the H₂O₂ + FGF-8 group compared to H₂O₂-treated cells as evidenced by TUNEL staining, a cell death detection ELISA, and cell viability. Levels of downstream apoptotic mediators, caspase-3 and caspase-9, were significantly (p < 0.05) upregulated following H₂O₂ treatment but were abrogated following FGF-8 application. Expression levels of Forkhead box protein O1 (FoxO-1), MnSOD, catalase, pAKT, and p-mTOR were significantly (p < 0.05) reduced in the H₂O₂ group (p < 0.05). Notably, these levels were significantly (p < 0.05) reversed following FGF-8 treatment. Our data, for the first time, suggest FGF-8 is an anti-apoptotic mediator in oxidative-stressed H9c2 cells. Furthermore, our data demonstrate that apoptotic inhibition by FGF-8 is consequent to FoxO-1 oxidative detoxification as well as augmentation to the PI3K/AKT cell survival pathway.