Effect of Curcumin Supplementation on Rat Skeletal Muscle Morphology and AMPK Levels: Study Protocol for a Randomized Controlled Trial

Background: Curcumin has been investigated as a potential natural solution to prevent or even treat skeletal muscle decline. There are a number of externally sourced finished products (ie, those imported from other countries) containing curcumin, but high cost limits their usage. The emerging research and development of locally sourced curcumin is an opportunity to produce high-quality oral supplements comparable to existing imported products. Objective: The primary purpose of this study is to determine the effects of oral administration of a local curcumin formulation on skeletal muscle using an animal model that similarly demonstrated the course of human sarcopenia. Methods: Purpose-bred 11- to 12-week-old female Sprague Dawley (SD) rats will be used in this study. SD rats are extensively used in animal models of human diseases and conditions such as diabetes, obesity and sarcopenia. Female rats have been selected because they do not demonstrate more temperature or activity variance and have more stable behavior compared to males. To simulate sarcopenia in this animal model, the tail suspension (TS) method was utilized. The TS method involves decreased hind limb function by suspending the animal’s tail for the duration of treatment. The laboratory animals will be randomized to receive any of the four treatments: (1) low-dose curcumin + vehicle; (2) high-dose curcumin + vehicle; (3) vehicle only; and (4) control (distilled water). The interventions will be subdivided into two: 2-week treatment and 4-week treatment. The gastrocnemius muscles on both sides will be excised and weighed, and the muscle tissues subjected to rapid freezing in acetone-dry ice and sliced into 10 μm-thick sections for staining. Examination of muscle architecture and computation of atrophy factors will be performed. The presence of connective tissue, fat tissue and number of atrophic muscle cells will be determined. Accurate quantitative detection of the rat total AMP (adenosine monophosphate)-Activated Protein Kinase will be performed in the gastrocnemius muscle tissue utilizing the enzyme-linked immunosorbent assay kit. Keywords: curcumin, sarcopenia, animal model