Quercetin modulates age-induced changes in the transcript levels of some apoptosis related genes in the skeletal muscles of male rats

Adverse changes occur gradually in the skeletal muscles with age via continuous exposure to oxidative stress. Quercetin, a member of the flavonoids family, possesses anti-oxidative and radical-scavenging activities. Therefore, this study investigated the role of quercetin to modulate age-induced changes in the transcript levels of some apoptosis-related genes in rat’s gastrocnemius muscles, up to 15 months-old. Half of the rats at each age (1, 5, 10 and 15 months old) were given a vehicle and the other half was given 200 mg/kg quercetin for 2 weeks, respectively. With the increase of age, vehicle groups showed hyalinization of the muscle fibers and a decrease of the catalase and an increase of the malondialdehyde levels. Down-regulation of Bcl2 gene and up-regulation of both NF-κB and Bax genes were recorded. Interestingly, quercetin groups showed focal hyalinization of the muscle fibers at both 10th and 15th months old. An increase in the catalase and a decrease in malondialdehyde levels, up-regulation of Bcl2 gene and down-regulation of both NF-κB and Bax genes were recorded. In conclusion, quercetin minimized age-induced alteration in the morphological structure and the expression of the apoptosis-related genes via increasing the antioxidant defense in the gastrocnemius muscle.随着年龄增长，机体骨骼肌因持续暴露于氧化应激环境中，会逐渐出现病理性改变。槲皮素(Quercetin)作为黄酮类化合物(flavonoids)家族成员，具备抗氧化与自由基清除活性。为此，本研究以月龄达15个月的大鼠腓肠肌为研究对象，探讨槲皮素对衰老诱导的部分凋亡相关基因转录水平变化的调控作用。本实验将各月龄（1、5、10及15月龄）大鼠均分为两组：对照组给予赋形剂，实验组则以200 mg/kg剂量灌服槲皮素，持续给药2周。随着月龄增长，对照组大鼠的肌纤维出现玻璃样变，过氧化氢酶(catalase)水平下降，而丙二醛(malondialdehyde)水平升高；同时检测到Bcl-2基因表达下调，核因子κB(NF-κB)与Bax基因表达上调。值得注意的是，槲皮素给药组大鼠仅在10、15月龄时出现局灶性肌纤维玻璃样变；该组大鼠的过氧化氢酶水平升高、丙二醛水平降低，Bcl-2基因表达上调，而核因子κB与Bax基因表达则出现下调。综上，槲皮素可通过增强大鼠腓肠肌的抗氧化防御能力，减轻衰老诱导的骨骼肌形态结构改变与凋亡相关基因表达异常。