c-peptide and Muscular-Atrophy

C-peptide therapy exerts several positive actions on nerves, vasculature, smooth muscle relaxation, kidney function and bone. To date, the role of C-peptide in preventing type 1 diabetes-related muscle atrophy has not been investigated. Our aim was to evaluate if C-peptide infusion prevents muscle wasting in diabetic rats.. Twenty-three male Wistar rats were randomly divided into three groups: normal control group, diabetic group and diabetic group plus C-peptide. Diabetes was induced by streptozotocin injection, and C-peptide was administered subcutaneously for 6 weeks. The blood samples were obtained at baseline, before streptozotocin injection and at the end of the study to assess C-peptide, ubiquitin and other laboratory parameters. We also tested the ability of C-peptide to regulate the skeletal muscle mass, the ubiquitin-proteasome system, the autophagy pathway as well as to improve muscle quality.. C-peptide administration reversed hyperglycaemia (P = 0.02) and hypertriglyceridaemia (P = 0.01) in diabetic plus C-peptide rats compared with diabetic control rats. The diabetic-control animals displayed a lower weight of the muscles in the lower limb considered individually than the control rats and the diabetic plus C-peptide rats (P = 0.03; P = 0.03; P = 0.04; P = 0.004, respectively). The diabetic-control rats presented a significantly higher serum concentration of ubiquitin compared with the diabetic plus C-peptide and the control animals (P = 0.02 and P = 0.01). In muscles of the lower limb, the pAmpk expression was higher in the diabetic plus C-peptide than the diabetic-control rats (in the gastrocnemius, P = 0.002; in the tibialis anterior P = 0.005). The protein expression of Atrogin-1 in gastrocnemius and tibialis was lower in the diabetic plus C-peptide than in diabetic-control rats (P = 0.02, P = 0.03). After 42 days, the cross-sectional area in the gastrocnemius of the diabetic plus C-peptide group had been reduced by 6.6% while the diabetic-control rats had a 39.5% reduction compared with the control animals (P = 0.02). The cross-sectional area of the tibialis and the extensor digitorum longus muscles was reduced, in the diabetic plus C-peptide rats, by 10% and 11%, respectively, while the diabetic-control group had a reduction of 65% and 45% compared with the control animals (both P < 0.0001). Similar results were obtained for the minimum Feret's diameter and perimeter.. C-peptide administration in rats could protect skeletal muscle mass from atrophy induced by type 1 diabetes mellitus. Our findings could suggest that targeting the ubiquitin-proteasome system, Ampk and muscle-specific E3 ubiquitin ligases such as Atrogin-1 and Traf6 may be an effective strategy for molecular and clinical intervention in the muscle wasting pathological process in T1DM.

Topics: Animals; C-Peptide; Diabetes Mellitus, Experimental; Male; Muscle, Skeletal; Muscular Atrophy; Proteasome Endopeptidase Complex; Rats; Rats, Wistar; Streptozocin; Ubiquitin

This study aimed to investigate the effects of C-peptide on C2C12 myotubes and a mouse model. Both in vitro and in vivo experiments were conducted to elucidate the role of C-peptide in muscle atrophy. Various concentrations (0, 0.01, 0.1, 1, 10, and 100 nM) of C-peptide were used on the differentiated C2C12 myotubes with or without dexamethasone (DEX). C57BL/6J mice were administered with C-peptide and DEX for 8 days, followed by C-peptide treatment for 12 days. Compared to the DEX group, C-peptide increased the fusion and differentiation indices and suppressed atrophic factor expression in C2C12 myotubes. However, 100 nM C-peptide decreased the fusion and differentiation indices and increased atrophic factor expression regardless of DEX treatment. In C57BL/6J mice, DEX + C-peptide co-treatment significantly attenuated the body and muscle weight loss and improved the grip strength and cross-sectional area of the gastrocnemius (Gas) and quadriceps (Quad) muscles. C-peptide downregulated the mRNA and protein levels of muscle degradation-related markers, particularly Atrogin-1, in Gas and Quad muscles. This study underscores the potential of C-peptides in mitigating muscle weight reduction and preserving muscle function during muscle atrophy via molecular regulation. In addition, the work presents basic data for future studies on the effect of C-peptide on diabetic muscular dystrophy.

Topics: Animals; C-Peptide; Dexamethasone; Mice; Mice, Inbred C57BL; Muscle Fibers, Skeletal; Muscle, Skeletal; Muscular Atrophy