Investigation of the relationship between plasma ghrelin levels and muscle atrophy in experimental diabetic rats.

In this study, the relationship between plasma ghrelin levels and muscle atrophy was examined in an experimental diabetic rat model. 56 male Wistar albino rats, aged 8-10 weeks, were used in the study. The rats were divided into 8 groupsD1: one-week diabetes, C1: one-week control, D2: three-week diabetes, C2: three-week control, D3: six-week diabetes, C3: six-week control, D4: eight-week diabetes, C4: eight-week control. To induce diabetes, rats were injected with a single intraperitoneal dose of 45 mg/kg streptozotocin. At the end of the experiments, body weights and fasting blood sugar levels were measured. mTOR and myostatin levels of gastrocnemius muscle and plasma ghrelin levels were measured by ELISA method. Gastrocnemius muscle weight, cross-sectional area and histopathological images were examined. It was observed that the gastrocnemius weights of the D2, D3, D4 groups decreased significantly compared to their controls (p≤0.01). Muscle cross-sectional area decreased significantly in groups D3 and D4 compared to controls (p≤0.01). Muscle mTOR levels were found to be significantly lower in all diabetic groups compared to controls (p≤0.01). Although muscle myostatin levels were higher in the diabetic groups, this increase was only significant in the D4 group. Plasma ghrelin levels were significantly lower in all diabetic groups compared to controls (p≤0.01). A positive correlation was determined between plasma ghrelin levels and the final weights, muscle cross-sectional area, gastrocnemius weights and mTOR levels of the rats. Time-dependent muscle atrophy developed in diabetic rats and there was a relationship between muscle atrophy and plasma ghrelin level. We suggest that ghrelin plays a role in diabetes-induced muscle atrophy as well as cachexia and sarcopenia.