【摘要】 目的探讨糖尿病大鼠骨骼肌超微结构变化的特点以及左旋卡尼汀(L-carnitine,L-CN)对其病理变化和脂肪酸代谢的影响。方法SD大鼠36只,随机分成对照组(NC组)、糖尿病组(DM组)和左旋卡尼汀组(L-CN组),每组12只,DM组和L-CN组腹腔注射链脲佐菌素(STZ)溶液65mg/kg·bw(12ml/kg·bw)复制糖尿病大鼠模型,L-CN组按照250mg/kg·bw剂量腹腔注射L-CN注射液,NC组按照体重注射1.5~2ml0.9%生理盐水。6周末处死大鼠,检测血清游离脂肪酸浓度,取各组大鼠股四头肌进行投射电镜观察。结果DM组游离脂肪酸较NC组明显增高(P<0.05);L-CN组游离脂肪酸浓度与NC组比较无显著差异(P>0.05)。电镜显示DM组骨骼肌细胞肌原纤维束排列整齐松散;线粒体数量减少,线粒体嵴结构不清、断裂,有絮状变性,空泡变性;骨骼肌毛细血管内皮细胞明显凸凹不平,有明显突起伸入管腔,使管腔狭窄,基底膜略增厚;骨骼肌中神经纤维髓鞘板层结构分离,崩解,髓鞘内神经纤维溶解。L-CN组电镜观察显示注射L-CN后可明显减轻上述病理改变。结论糖尿病可导致骨骼肌超微结构的改变并以线粒体改变较为明显,补充L-CN可以降低游离脂肪酸浓度,防治糖尿病骨骼肌超微结构的病变。更多还原

【Abstract】 Objective To investigate the characteristics of ultrastructural alterations of skeletal muscle and the effect of L-carnitine on pathological changes and fatty acid metabolism in diabetic rats.Methods Thirty-six SD rats were randomly divided into three groups(n=12each):the control group(NC group)、the diabetes group(DM group) and the carnitine group(L-CN group).The diabetes rat model was established by intraperitoneal injection of 65mg/kg.bw (12ml/kg.bw) streptozotocin(STZ) solution in DM group and L-CN group.L-CN group were treated by injection of L-carnitine according to 250mg/kg.bw injection dose.NC group were treated by injection of 1.5-2ml 0.9%N.S according to weight.At the end of the 6th week,all rats were sacrificed.Blood samples were collected for determination of free fatty acid concentrations,and quadriceps samples were collected for electron microscopy observation.Results After six weeks the levels of free fatty acid were significantly higher in DM group than those in NC group (P<0.05);While there was no significant difference in the levels of free fatty acid between L-CN group and NC group(P>0.05).Under electron microscopy,the muscle fiber bundle of skeletal muscle cells ranked neatly and loosely in DM group;the number of mitochondria decreased,mitochondrial ridge structure present as unclear、breakage、flocks and Vacuolation degeneration;skeletal muscle capillary endothelial cells present as rugged obviously,which protruded into the lumen、narrowed the lumen and thickened the basement membrane;in skeletal muscle nerve fibers myelin lamellar structure present as isolation、collapse,and intrathecal nerve fibers present as Dissolved.While in L-CN group these pathological changes were reduced obviously after injection of L-CN.Conclusions Diabetes can lead to ultrastructure alterations of skeletal muscle,among which the changes of Mitochondria are the most obvious.Supplying of L-CN can reduce the concentrations of free fatty acids and combat ultrastructure alterations of skeletal muscle in diabetes.更多还原