热应激预处理对离心运动大鼠骨骼肌自由基代谢的影响

背景：研究表明热预处理能够提高肌肉抗损伤的能力,但具体的机制尚不清楚。目的：观察热应激预处理对离心运动大鼠骨骼肌超氧化物歧化酶活性及丙二醛含量的影响。方法：雄性Wistar大鼠随机分为对照组、离心运动组、预热应激＋离心运动组。热应激温度为43℃,时间约35min。采用-16°下坡跑台跑做大负荷间歇性离心运动,跑速为26.8m/min,运动5min,间歇1min,共进行10组。分别于运动前1h、运动后1,24,48h取大鼠腓肠肌,采用硫代巴比妥酸法测定大鼠丙二醛含量,黄嘌呤氧化酶法测定超氧化物歧化酶活性。结果与结论：与对照组比较,离心运动组大鼠腓肠肌丙二醛含量显著增高（P〈0.05）,并随运动后时间的延长逐渐升高,超氧化物歧化酶活性随运动后时间的延长显著降低（P〈0.05）。与离心运动组比较,预热应激＋离心运动组大鼠腓肠肌超氧化物歧化酶活性显著增高（P〈0.05）,丙二醛含量显著降低（P〈0.05）。说明热应激预处理可增强骨骼肌超氧化物歧化酶活性,降低丙二醛含量,对离心运动损伤有保护作用。

Effects of pretreatment with heat stress on free radical metabolism in skeletal muscle of rats after eccentric exercise

BACKGROUND：It has been demonstrated that pre-heat stress can elevate the ability of muscle against injury,but the precise mechanism is unclear.OBJECTIVE：To observe the effect of pre-heat stress on superoxide dismutase activities and malondialdehyde content in rat skeletal muscle after eccentric exercise.METHODS：Male Wistar rats were randomly divided into control group,eccentric exercise group,heat stress＋eccentric exercise group.The temperature of heat stress was 43 ℃ for about 35 minutes.Large load intermittence eccentric exercise was performed at-16° down slope treadmill at 26.8 m/min for 5 minutes,with an interval of 1 minute,totally for 10 groups.Rat gastrocnemius muscle was obtained at 1 hour before exercise,1,24 and 48 hours after exercise separately.Rat malondialdehyde content was determined by thiobarbituricacid method.Superoxide dismutase activities were measured by xanthine oxidase method.RESULTS AND CONCLUSION：Compared with control group,malondialdehyde content was significantly increased in rat gastrocnemius muscle in eccentric exercise group（P 0.05）,and gradually increased over time after exercise.Superoxide dismutase activities were significantly decreased over time after exercise（P 0.05）.Compared with eccentric exercise group,superoxide dismutase activities were significantly increased（P 0.05）,but malondialdehyde content（P 0.05） was significantly decreased in rat gastrocnemius muscle of heat stress＋eccentric exercise group.These indicate that heat stress can enhance superoxide dismutase activities,reduce malondialdehyde content,and protect skeletal muscle from eccentric exercise induced injury.