The Green Tea Catechin, EGCg, Preserves Both Muscle and Bone in Aging Sarcopenic Rats

Abstract

ObjectivesSarcopenia is the progressive decline in muscle mass, strength and function that is exacerbated with age. It is well known that there is an overlap between sarcopenia and osteopenia/osteoporosis in the aging population. Thus, addressing both muscle and bone loss during aging is important. Epigallocatechin gallate (EGCg) is the most abundant green tea catechin and has well established anti‐inflammatory and antioxidant benefits. Green tea consumption has also been associated with bone health. In this study we examined the impact of chronic EGCg treatment on muscle mass and bone structure in aging rats.MethodsAged male Sprague‐Dawley rats (21 months) were fed the following diets ad libitum: Control group (n=9) fed AIN93M diet, and a treatment group (n=10) fed AIN93M diet +EGCg (200 mg/kg) for 8 weeks. At the end of study, gastrocnemius muscles were weighed, and histological analysis was performed to measure muscle fiber cross sectional area (CSA) using hematoxylin & eosin staining. Bones were analyzed by MicroCT imaging (Burker) of the tibia at ~22 μm resolution and images were processed using Inveon Research Workplace software. All bone samples were analyzed for trabecular bone volume, trabecular number, trabecular spacing, trabecular thickness, trabecular pattern factor and bone density.ResultsGastrocnemius muscle wet weights were significantly higher (p<0.05) and fiber CSA tended to be higher (p<0.06) in the EGCg group compared to controls. Tibia bone volume/total volume density was significantly greater (p=0.03) in animals treated with EGCg compared to control. Significant differences were found in trabecular microstructure, with a significant increase in trabecular number per given volume (p=0.01) and a corresponding significant decrease in trabecular spacing (p=0.02) in EGCg‐treated rats compared to control. No significant group differences were found in overall bone density or trabecular thickness. Differences in mean values between control and EGCg groups were determined by student’s t‐test.ConclusionsThese data present novel findings on the osteoprotective mechanism of EGCg on the aging bone through an increase in trabecular bone volume, trabecular number and trabecular spacing. Furthermore, the preservation of muscle mass and muscle fiber CSA suggests that the use of green tea catechin, EGCg, could be a potential nutritional therapy to prevent the progression of muscle and bone loss during sarcopenia.Support or Funding InformationAbbott Nutrition