不同频率中等负荷跑台训练对D-半乳糖致衰老大鼠心肌结构及SOD、MDA的影响

目的:探讨不同频率中等负荷跑台训练对D-半乳糖致衰老大鼠心肌形态结构及生化指标的影响。方法:2月龄大鼠40只,随机分为正常对照组(NC组)、衰老模型对照组(AC组)、衰老模型训练Ⅰ组(AEⅠ组)和衰老模型训练Ⅱ组(AEⅡ组),每组10只。AC组、AEⅠ组和AEⅡ组每日在颈背皮下注射一次D-半乳糖(125 mg/kg)。AC组常规喂养,不训练;AEⅠ组和AEⅡ组采用坡度为零的跑台训练,第1周每天运动15 min,以后每周增加5 min,直至第6周每天40 min。AEⅠ组每周隔天训练,AEⅡ组每周训练6天,周日休息。6周后,测定各组大鼠心肌丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性,光镜观察心肌结构。结果:AEⅠ组和AEⅡ组大鼠心肌SOD活性显著高于AC组,MDA含量显著低于AC组(P<0.01);AEⅡ组心肌MDA含量显著高于NC组(P<0.01)。光镜结果显示:NC组大鼠单位面积心肌纤维面积百分比最大,AC组最小,AEⅠ组大鼠心肌纤维面积百分比大于AEⅡ组,心肌纤维数量较多,排列整齐;胞核清晰,嵴排列整齐规则且密集。结论:不同频率中等负荷运动有效改善D-半乳糖致衰老大鼠心肌结构,提高心肌抗氧化能力。

Effect of Moderate Intensity Treadmill Running with Different Frequencies on the Structure, SOD and MDA of Myocardium in D-galactose-induced Aging Rat

Objective This experiment aims to explore the effect of moderate intensity treadmill running with different frequencies on the morphology and biochemical parameters of myocardium in Dgalactose-induced aging rat. Methods 40 two-month-old male rats were divided randomly and equally into normal control group(NC),aging control group(AC),aging exercise groupⅠ(AEⅠ),aging exercise groupⅡ(AEⅡ). Rats in groups AC,AEⅠand AEⅡ were injected with D-galactose(125 mg/kg/d) once a day. Rats in AEⅠand AEⅡran on a treadmill 15 min per day in the 1st week and 5 min increasing weekly up to 40 min a day in the 6th week. AEⅠgroup ran every other day and AEⅡgroup 6 day per week. After 6 weeks training,myocardial structure,malondialdehyde (MDA) and activities of superoxide dismutase (SOD) were observed. Results Compared with the AC group,the activities of SOD increased observably,and MDA decreased evidently in both AEⅠand AEⅡgroups (P < 0.01). Compared with NC group,MDA in AE Ⅱ group increased significantly (P < 0.01). The highest percentage of myocardial fiber per unit area was found in NC group,and the lowest in AC group. Percentage of myocardial fiber per unit area in AEⅠgroup was higher than in AEⅡ group. Increased number of myocardial fiber,fiber lining up in order,clear cell nucelus,neat crest arrangement were observed in AEⅠgroup. Conclusion Moderate intensity and proper frequency of exercise effectively improve the cardiac structures,increase myocardial antioxidant capacity in aging rats.