促黑素对小鼠骨骼肌细胞脂肪酸氧化的影响

Effect of α-MSH on fatty acid oxidation in mouse skeletal muscle

目的观察α-促黑素(α-MSH)对小鼠骨骼肌细胞脂肪酸氧化的影响及其机制。方法 8周龄C57BL/6J小鼠分成生理盐水对照组和实验组(α-MSH组),两组分别皮下注射生理盐水和α-MSH后0、0.5、1、3、5h测定比目鱼肌的脂肪酸氧化限速酶-肉毒碱棕榈酰转移酶-1(CPT-1)活性。体外培养的原代骨骼肌细胞和C2C12细胞,利用RT-PCR法测定黑皮质素受体(MCR)的表达,并α-MSH处理2h后观察脂肪酸氧化。结果α-MSH皮下注射后1、3h时CPT-1活性显著增加,与对照组相比差异有统计学意义(P<0.05)。原代骨骼肌细胞和C2C12细胞中表达MC1R、MC3R、MC4R和MC5R,α-MSH剂量依赖性地促进脂肪酸氧化。结论α-MSH可能通过MCR促进骨骼肌细胞脂肪酸氧化。

Objective To investigate the effect and mechanism of α-Melanocyte stimulating hormone（α-MSH）on fatty acid oxidation in skeletal muscle.Methods Saline or α-MSH were subcutaneously injected into 8-week C57BL/6J male mice,and the carnitine palmitoyl transferase-1（CPT-1）activities were measured 0,0.5,1,3 and 5 hours after treatment.Melanocortin receptor（MCR）subtypes in the muscle and C2C12 cells were measured by RT-PCR,and the effect of α-MSH on palmitate oxidation was also analyzed.Results CPT-1 activities were significantly increased 1 and 3 hours after treatment（P0.05）.MC1R,MC3R,MC4R and MC5R were expressed in C2C12 cells and primary cultured skeletal muscle,and α-MSH increased the palmitate oxidation in a dose-dependent way.Conclusion α-MSH might increased fatty acid oxidation in skeletal muscle through MCR.