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目的:观察补充烟酸对单次离心运动大鼠骨骼肌增殖细胞核抗原(PCNA)蛋白表达的影响。方法:90只成年雄性Sprague-Dawley(SD)大鼠(重190～220g)随机等分为对照组和烟酸组,各组再依次分为安静对照组、运动后即刻组、运动后24小时组、运动后48小时组及运动后72小时组。进行一次性下坡跑,速度18m/min,坡度-16°,持续运动120分钟。正式运动前3日开始,每日上午,烟酸组大鼠给予烟酸水溶液(10mg/kg)灌胃,对照组给予等体积饮用纯净水,持续至取材日。离心运动当日运动前30分钟进行灌胃。腹主动脉取血测CK(酶动力学方法)和LDH(比色法)水平,取左侧比目鱼肌,采用Western blotting方法测试胞核PCNA蛋白表达。结果:单次离心运动后即刻,烟酸组大鼠PCNA表达量显著上升,明显高于安静时水平,48小时达峰值,并显著高于其它时间点,72小时下降但仍显著高于安静值。对照组大鼠运动后即刻、24小时PCNA表达量与安静时相似,48小时升高,显著高于安静时水平,72小时下降近安静值。运动后24小时两组大鼠血清CK和LDH值显著高于安静值,运动后48小时CK下降近安静值,LDH于运动后48小时下降,72小时近安静值。相同时间点比较,烟酸组大鼠运动后24小时PCNA表达量显著高于对照组,其他时间点差异不显著,各时间点CK与LDH值两组均无明显差异。结论:补充烟酸不影响单次离心运动后大鼠血CK和LDH值,但明显增加其骨骼肌PCNA蛋白表达量,可能有利于由肌卫星细胞驱动的损伤骨骼肌的修复和再生过程。
Objective: To observe the effects of niacin supplementation on the expression of proliferating cell nuclear antigen (PCNA) protein in single eccentric exercise rats. Methods: Ninety adult male Sprague-Dawley (SD) rats (weighing 190-220 g) were equally divided into control group and nicotinic acid group. Each group was divided into quiet control group, immediate exercise group, exercise group 24 hours Group, 48 hours after exercise and 72 hours after exercise. A one-time downhill run, speed 18m / min, gradient -16 °, continuous exercise 120 minutes. Beginning 3 days before the formal exercise, daily niacin group rats were given niacin aqueous solution (10mg / kg) orally, and the control group were given equal volume of purified drinking water, until the date of application. Centrifuge exercise 30 minutes before exercise on the day of gavage. Abdominal aorta were taken for CK (enzyme kinetic assay) and LDH (colorimetric method), and the left soleus muscle was taken. The expression of PCNA protein in nucleus was detected by Western blotting. Results: Immediately after single eccentric exercise, the expression of PCNA in niacin group increased significantly, significantly higher than that of resting state, peaked at 48 hours, significantly higher than other time points, decreased at 72 hours but still significantly higher than resting values . Immediately after exercise, the expression of PCNA in control group at 24 hours was similar to that at rest, increased at 48 hours, significantly higher than that at rest, and decreased at 72 hours. Serum CK and LDH values of the two groups of rats were significantly higher than resting values at 24 hours after exercise. CK decreased to near resting values 48 hours after exercise, LDH decreased 48 hours after exercise, and reached near resting values at 72 hours. At the same time point, the expression of PCNA in niacin group was significantly higher than that in control group 24 hours after exercise, and the difference was not significant at other time points. There was no significant difference between CK and LDH at each time point. CONCLUSION: Nicotinic acid supplementation does not affect the CK and LDH values in rats after single centrifugation, but significantly increases the expression of PCNA protein in skeletal muscle, which may be beneficial to the repair and regeneration process of injured skeletal muscle driven by muscle satellite cells.