Increasing studies report that many natural products can participate in formation of muscle fibers. This study aimed to investigate the effect of lycopene on skeletal muscle-fiber type in vivo and in vitro. C2C12 myoblasts were used in vitro study, and the concentration of lycopene was 10 µM. In vivo, 8-week-old male C57/BL6 mice were used and divided into four groups (n=8): (1) ND: normal-fat diet; (2) ND+Lyc: normal-fat diet mixed with 0.33% w/w lycopene; (3) HFD: high-fat diet; and (4) HFD+Lyc: high-fat diet mixed with 0.33% w/w lycopene. The mice tissue samples were collected after 8 weeks feeding.

We found that lycopene supplementation enhanced the protein expression of slow-twitch fiber, succinate dehydrogenase, and malic dehydrogenase enzyme activities, whereas lycopene reduced the protein expression of fast-twitch fibers, lactate dehydrogenase, pyruvate kinase enzyme activities. Moreover, lycopene can promote skeletal muscle triglyceride deposition, enhanced the mRNA expression of genes related to lipid synthesis, reduced the mRNA expression of genes related to lipolysis. And high-fat diet-induced dyslipidemia and oxidative stress were attenuated after lycopene supplementation. Additionally, lycopene supplementation reduced the glycolytic reserve but enhanced mitochondrial ATP production in C2C12 cells.

These results demonstrated that lycopene affects the activities of metabolic enzymes in muscle fibers, promotes the expression of slow-twitch fibers, and enhanced mitochondrial respiratory capacity. We speculated that lycopene affects the muscle-fiber type through aerobic oxidation, suggesting that lycopene exerts potential beneficial effects on skeletal muscle metabolism.

越来越多的研究报告称，许多天然产物可以参与肌肉纤维的形成。本研究旨在研究番茄红素在体内和体外对骨骼肌纤维类型的影响。C2C12成肌细胞用于体外研究，番茄红素浓度为10μM。在体内，使用8周龄雄性C57/BL6小鼠并分为四组（n =8）：（1）ND：正常脂肪饮食；(2) ND+Lyc：正常脂肪饮食与 0.33% w/w 番茄红素混合；(3)HFD：高脂肪饮食；(4) HFD+Lyc：高脂肪饮食与 0.33% w/w 番茄红素混合。喂养8周后收集小鼠组织样品。

我们发现补充番茄红素增强了慢肌纤维、琥珀酸脱氢酶和苹果酸脱氢酶活性的蛋白质表达，而番茄红素降低了快肌纤维、乳酸脱氢酶、丙酮酸激酶活性的蛋白质表达。此外，番茄红素可促进骨骼肌甘油三酯沉积，增强脂质合成相关基因的mRNA表达，降低脂解相关基因的mRNA表达。补充番茄红素后，高脂饮食引起的血脂异常和氧化应激减弱。此外，番茄红素补充剂减少了糖酵解储备，但增强了 C2C12 细胞中线粒体 ATP 的产生。

这些结果表明番茄红素影响肌肉纤维中代谢酶的活性，促进慢肌纤维的表达，增强线粒体呼吸能力。我们推测番茄红素通过有氧氧化影响肌肉纤维类型，表明番茄红素对骨骼肌代谢发挥潜在的有益作用。