SKELETAL MUSCLE CONTRACTILE FUNCTIONS IN STREPTOZOTOCIN INDUCED TYPE 1 DIABETES MELLITUS

Abstract

Background: This study was carried out to evaluate the contractile functions of slow and fast skeletal muscles in streptozotocin induced type 1 diabetic female Sprague Dawley rats. Methods: Thirty healthy female Sprague Dawley rats were divided into two groups. The rats in group I (female control, n=15) were fed on normal pellet diet and water ad libitum. The rats in group II (female diabetic, n=15) were rendered diabetic by single intraperitoneal injection of streptozotocin (STZ) 65 mg/Kg body weight. At the end of four weeks, contractile parameters of slow soleus and fast extensor digitorum longus (EDL) muscles were recorded by iWorx^® advanced animal/human physiology data acquisition unit (AHK/214). Results: At the end of four weeks, time to peak twitch tension (TPT) and time taken to relax to 50% of the peak twitch tension (HRT) in isolated soleus muscle of the female diabetic group were significantly longer (p<0.001) compared to control group. On the contrary, TPT and HRT in isolated EDL muscle of the diabetic group were similar to the control group. Maximum fused tetanic tension in isolated soleus muscle of the diabetic group was similar to the control group. On the contrary, maximum fused tetanic tension in isolated EDL muscle of the female diabetic group was significantly lower (p<0.001) as compared to the control group. Conclusion: It is concluded that streptozotocin induced type 1 diabetes mellitus manifests differential effects on the contractile properties of slow and fast skeletal muscles of female Sprague Dawley rats.