تاثیر یک دوره تمرین مقاومتی بر سطح drp1 در بافت قلب رت‌های چاق مبتلا به دیابت نوع 2

زمینه و هدف: شکافت میتوکندری قلبی با مقاومت به انسولین در دیابت نوع دو نقش اساسی دارد. هدف از انجام تحقیق تجربی حاضر بررسی تاثیر یک دوره تمرین مقاومتی بر سطح drp1 در بافت قلب رت های چاق مبتلا به دیابت نوع 2 بود. روش کار: برای انجام این تحقیق 14 سر رت نر ویستار 10 هفته ای از مرکز انستیتو پاستور ایران تهیه شده و به طور تصادفی به دو گروه کنترل و تمرین مقاومتی تقسیم شدند. ابتدا رت ها هشت هفته رژیم غذایی پرچرب دریافت کرده و پس از رسیدن به وزن مطلوب با تزریق stz (25 میلی لیتر بر کیلوگرم وزن بدن) دیابتی شدند. پروتکل تمرین مقاومتی شامل 5 جلسه، هر جلسه 5 ست 4 تکراری در هفته اول با 30 درصد وزن بدن شروع شده و در هفته هشتم به 100 درصد وزن بدن رسید. میزان بیان ژن drp1 با استفاده از روش real time – pcr اندازه گیری شد. جهت تجزیه و تحلیل داده ها از آزمون t مستقل در سطح معنی داری p<0.05 استفاده شد. یافته ‌ها: نتایج نشان داد که تمرین مقاومتی باعث کاهش سطح گلوکز خون در مقایسه با گروه دیابتی کنترل شد (0.001≥p). سطح انسولین خون رت های دیابتی تمرین کرده در مقایسه با گروه کنترل دیابتی به طور معنی داری بیشتر بود (0.01≥p). بیان ژن drp1 در گروه دیابتی تمرین کرده در مقایسه با گروه دیابتی کنترل کاهش معنی داری نشان داد (0.001≥p). نتیجه ‌گیری: با توجه به یافته های تحقیق استفاده از تمرینات مقاومتی جهت کاهش عوارض چاقی و دیابت با مشورت پزشک به افراد دیابتی توصیه می شود.

the effect of a resistance training course on drp1 level in heart tissue of obese rats with type 2 diabetes

background & aims: diabetes is the most common cause of renal diseases, new cases of blindness, and non-traumatic amputation. prevalence of cardiovascular diseases among type 2 diabetic patients is four times more than other individuals of a society (4). diabetic cardiomyopathy is the deterioration of performance and morphology of myocardium which results from disturbances of glucose hemostasis in the diabetic condition and occurs independently from coronary disease. in the cell level, diabetic cardiomyopathy is characterized by hypertrophy of the heart cells, fibrosis, and apoptosis (5). shortage of energy in the heart muscle is related to the commencement and development of different heart diseases including the conditions observed during insulin resistance and type-2 diabetes (6). in the condition of insulin resistance, the power of heart muscle declines to use glucose as the source of energy. this change in the preferred substrate has a vital role in the pathogenesis of diabetic cardiomyopathy (7). mitochondria are highly congested in the heart and occupy 30 percent of heart cells, and produce over 90 percent of intracellular atp which is consumed by heart (8). therefore, many studies, nowadays, have focused on the mitochondrial function disorder as a causative factor for metabolic disorders and heart diseases which are connected with insulin resistance.  mitochondria are dynamic organelles which continuously change their morphology in response to intercellular conditions through fusion and fission, and a change in the balance of these processes affects different biological events including cell division, apoptosis, autophagy, and metabolism (9). mitochondrial fission is mainly controlled by the protein which is connected to cytoplasmic dynamin gtpases 1 (drp1) (10).   to the best knowledge of the researchers of the present study, there are few studies which particularly show the direct relationship between cardiac mitochondria fission, insulin resistance and diabetes type 2. however, it is well known that the main contributor which triggers diabetic cardiomyopathy is the oxidative stress resulted from hyperglycemia (11). makino et al. in a different but related model showed that mitochondria fragmentation in the cardiac endothelial cells which were obtained from the heart of diabetic rats resulted in an increase in the level of drp 1 (15). sports and exercises are prescribed as a part of therapeutic methods for heart disease patients since these activities decrease heart risk factors, protect myocardium and improve heart performance (18). exercises are also suggested as a non-medicinal therapy for type 2 diabetic patients because they have numerous benefits including improvement of insulin sensitivity and weight loss (19-21). the present experimental study was designed aiming to investigate the effect of one course of resistance training on the fasting levels of blood glucose and insulin also drp1 in the cardiac tissue of type-2 diabetic obese rats.  methods: in order to conduct the present study, initially 14 wistar male rats with an average age of 10 weeks and average weight 220 ± 20 were obtained from pasteur institute of iran. the rats were then randomly divided into two groups of control (7 rats) and resistance training (7 rats). to induce diabetes type 2, the rats were initially fed a high-fat diet. after the rats reached the required weight, they were made diabetic by intraperitoneal injection of stz (25 ml / per kg of weight).  resistance training protocol: the rats in the resistance training group participated in an 8-week resistance training program (5 sessions a week) starting at the 18th week. each session included 5 sets; and each set consisted of 4 repetitions of carrying a weight through the ladder with rest intervals of 2 minutes between sets and 30 seconds between repetitions.