Effect of insulin-like growth factor-1 on expression of stem cell factor from sepsis rat colonic smooth muscle cell / 中国综合临床

ABSTRACT

Objective To explore the effect and intracellular signal transduction pathway of insulin-like growth factor 1 (IGF-1) on the expression of stem cell factor (SCF) in spesis rats colonic smooth muscle cells (SMC).Methods The model of spesis rats was established,colonic SMC from spesis rats were cultured by enzymolysis and identified by α-actin immunofluoresence methods.Colonic SMC incubated with different concentrations (0,50,100 and 150 μg/L) of IGF-1 for different durations (0,12,24,36 and 48 h),and another SMC were pretreated with specific mitogen-activated protein kinase (MEK) inhibitor PD-98059 and phosphatidylinostiol 3-kinase(PI 3-kinase) inhibitor LY-294002 before IGF-1 induced.The expression of SCF in colonic SMC was examined by Western blot and quantitative reverse transcription polymerase chain reaction.Results (1) A very low level of SCF was expressed in colonic SMC cultured in bovine serum free medium.The protein and mRNA were 0.223 ± 0.047 and 0.149 ± 0.023 respectively.The expression of SCF protein and mRNA from SMC was increased to 0.398±0.033 and 0.243±0.013(P＜0.05) when concentration of IGF-1 was 50 μg/L.The final effective concentration of IGF-1 in vitro was 100 μg/L,the levels of SCF protein and mRNA were increased to 0.719±0.017 and 0.360±0.006(P＜0.05).(2) For the time point induced the SCF expression by IGF-1,the expression level of protein and mRNA in 0 h were 0.347±0.031 and 0.092 ±0.018 respectively.The time point of SCF peak level occurred at the 24 h,the expression level of SCF protein and mRNA were increased to 0.893 ± 0.049 and 0.396 ± 0.048 (P ＜ 0.05).(3) The IGF-1-induced SCF expression was reduced significantly by a pretreatment of PD-98059 (SCF protein and mRNA were reduced 37％ and 45％,P＜0.05),and LY-294002 had no effect on the expression of SCF (P＞0.05).Conclusion The expression of SCF from colon SMC in sepsis rat is stimulated by IGF-1 in both dose and time-dependent manners,in which ERKMAPK signal transduction may play an important role.