The effect of wild bitter gourd in an aging-induced sarcopenia mouse model

• Main Authors: Yi-An Lai, 賴怡安
• Other Authors: Ching-Jang Huang
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/w83jz8

碩士 === 國立臺灣大學 === 生化科技學系 === 107 === Sarcopenia, an age-related decline in muscle mass, strength, and physical function, is of great concern in the public health of ageing societies. Mitochondrial dysfunction, a hallmark of aging, is thought to play a major role in the pathogenesis of sarcopenia. Cellular senescence, a response characterized by a stable growth arrest and other phenotypes including a proinflammatory secretome, has been implicated as a major cause of age-related diseases. While wild bitter gourd has been reported to up-regulate mitochondrial oxidative capacity, improve exercise performance and reduce fatigue in castrated and ICR mice, this study aims to evaluate the effect of wild bitter gourd on mitochondrial oxidative capacity in an age-induced sarcopenia mouse model. Three groups of aging C57BL/6J male mice (16.5-month old) were fed the AIN-93G diet (the AN group) or its modified versions, which contained 50% w/w sucrose without (the AH group) or with 5% w/w wild bitter gourd powder (BGP) supplementation (the AHB group) for 26 weeks. Two more groups of 3-month old mice served as the young controls for AN & AH group, denoted as YN group and YH group. At the 22nd week of the feeding period, the latency to fall and holding impulse in the inverted screen test of the AHB group were 19% and 10% higher than the AH group respectively, and were comparable to the young groups (p>0.05). At necropsy, BGP supplementation restored the age-related decline in the relative gastrocnemius (GAS), soleus, tibialis anterior, and extensor digitorum longus weight (p<0.05). The percentage of large cross section area (CSA) fibers in GAS and TA of the AHB group was higher than the AH group for 9.71 and 18.92% respectively (p<0.05).The percentage of high succinate dehydrogenase (SDH) activity fibers of the AHB group increased 23% in GAS comparing to the AH group (p<0.05). Compared to the AH group, the AHB mice showed up-regulated mRNA expressions of the Pgc1α gene, the master regulator of mitochondrial biogenesis, Ucp2 (ubiquitous uncoupling protein) and Myh7 (marker of type I fiber) genes and down-regulated Myh4 (type II fiber marker) in the GAS muscle (p<0.05). On the other hand, results from two-way ANOVA of data from AN, AH, YN and YH groups showed significant up-regulations of senescence-related genes in the GAS and liver of aged mice (p<0.05). The AHB group showed downregulated p16 mRNA gene expression in liver. Nevertheless, expression levels of the senescence related genes were comparable to the AH group in the GAS of AHB group (p>0.05). In conclusion, these results suggested that BGP could improve muscle function and mitochondrial oxidative capacity, probably through increasing mitochondrial biogenesis and through inducing fiber type conversion in skeletal muscle and might provide a potential strategy to prevent sarcopenia.