Abstract：OBJECTIVE: This study examined the effect of rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), on eukaryotic initiation factor (eIF- 4E) expression in rat myocardial fibroblasts infected by Coxsackievirus B3 (CVB3) in order to identify the drug target for treatment of viral myocarditis. METHODS: Primary cultured rat myocardial fibroblasts were treated with CVB3 with multiplicity of infection (MOI=0.5 PFU/cell). The experiment consisted of four groups in which the cultured rat fibroblasts cells were treated with CVB3, rapamycin (10 nM) and CVB3 + rapamycin or placebo (control). Experimental model of CVB3-infected myocardial fibroblasts was confirmed by detection of CVB3 mRNA expression with RT-PCR and observation of morphological changes of the infected cells with microscopy. eIF-4E expression was determined by both RT-PCR and Western Blot methods. RESULTS: Morphological changes were found in the fibroblasts treated with MOI 0.5 PFU/cell of CVB3 by transmission electron microscope and the viral particles were found in the cytoplasm. CVB3 mRNA was expressed in CVB3-infected fibroblasts after 1, 2, and 3 days after infection and 2 days after passage. The gray scale values of the eIF- 4E /β-actin in the control, the CVB3, the rapamycin and the CVB3+rapamycin groups were 0.73±0.07, 0.87±0.03, 0.32±0.03 and 0.56±0.04 respectively detected by RT-PCR, and were 0.79±0.09, 1.35±0.12, 0.55±0.04, and 0.62±0.07 respectively detected by Western blot. EIF- 4E expression in the CVB3 group was higher than that in the control group. Both the rapamycin and the CVB3+rapamycin groups had lower eIF- 4E expression than the control and the CVB3 groups. CONCLUSIONS: CVB3 can infect myocardial fibroblasts and up-regulate the eIF- 4E expression in rat myocardial fibroblasts. Rapamycin can inhibit eIF- 4E expression and may be a potential medicine for treatment of viral myocarditis. It was suspected that mTOR/eIF- 4E signal pathway in rat myocardial fibroblasts might play an important role in the pathogenesis of viral myocarditis.［Chin J Contemp Pediatr, 2007, 9 (6):587-590］
CHEN Chun-Yuan,SUN YUE-Nu,YANG Zuo-Cheng et al. Rapamycin affects eIF- 4E expression in rat myocardial fibroblasts infected by Coxsackievirus B3[J]. CJCP, 2007, 9(6): 587-590.
