Assessment of skeletal muscle early myopathy with contrast-enhanced ultrasound in rabbit model of diabetes mellitus

Objective To evaluate early skeletal muscle myopathy with contrast-enhanced ultrasound (CEUS) in diabetic rabbits. Methods Alloxan (100 mg/kg) was given intravenously to 11 New Zealand white rabbits. Another 5 age-matched normal rabbits were used as controls.CEUS was performed at baseline and 1, 2, 3 months after the establishment of diabetes, respectively. Then, skeletal muscle samples were obtained for pathological observation. Additionally, the diabetic rabbits were divided into 3 groups according to their pathologic findings: mild, moderate, and severe myopathy group. Micro-perfusion parameters, including artery-to-vein transit time (A-VTT), muscle tissue mean transit time (M-MTT) and muscle tissue peak intensity (M-PI) were calculated. Results The diabetic rabbits exhibited a lower body weight increase and a decrease of muscle thickness.Plasma levels of triglyceride, cholesterol and creatinine were significantly higher in diabetic group than those in control group (P<0.05). The A-VTT and M-MTT values of the diabetic rabbits significantly increased over time (all P<0.05), whereas M-PI value significantly decreased compared with that in control group (P=0.013). Besides, the A-VTT value was significantly higher in severe myopathy group than that in mild group (P=0.001). The M-MTT values in both moderate and severe groups were significantly higher when compared to that in mild group (all P<0.05). The A-VTT and M-MTT values were correlated with the severity of diabetic myopathy(ρ=0.898, P<0.001; ρ=0.527, P=0.01). Conclusions Diabetic rabbits have defective skeletal muscle micro-perfusion in the early stage. CEUS can quantify impaire muscle microcirculation, and is a valuable tool for assessment of diabetic myopathy. Key words: Contrast-enhanced ultrasound; Diabetes mellitus; Myopathy; Microcirculation