姜黄素预处理对干热环境大鼠骨骼肌组织学及超微结构变化的影响

目的 探讨姜黄素预处理对干热环境暴露大鼠骨骼肌的影响。方法 选取6～8周龄SPF级雄性SD大鼠200只，每组40只，随机分组(盐水组、溶剂组、姜黄素低剂量预处理组、姜黄素中剂量预处理组、姜黄素高剂量预处理组)，各组连续7 d等体积灌胃，第8天置于西北特殊环境人工实验舱，设定沙漠干热环境气候模式[(温度(41±0.5)℃，湿度(10±1)%)]，分别在0 min、50 min、100 min、150 min时间点，各组随机取10只出舱麻醉，采集下腔静脉血液用于测定肌红蛋白含量；取部分股二头肌于甲醛溶液中固定用于光镜下观察，随机选取5个视野对白肌进行灰度测量,于50 min、150 min从盐水组、姜黄素高浓度组大鼠股二头肌中取1 mm×1mm×1 mm组织块置于锇酸中固定用于透射电镜观察。结果 1.光镜下观察结果显示：盐水组、姜黄素高浓度组在干热环境中随时间延长同根肌纤维部分区域颜色变淡，变淡区域逐渐增多，盐水组变淡区域逐渐变为白色，姜黄素高浓度组变淡区域呈淡红色；并且随时间延长颜色变淡的肌纤维数量逐渐增多，尤其盐水组增多明显； 2.透射电镜观察表明干热环境盐水组以线粒体减少为主要组织学改变；姜黄素高浓度组与盐水组相比线粒体数量减少的较少，姜黄素高浓度组可见线粒体堆集的增生迹象；3.干热环境中各组血液中肌红蛋白含量无显著变化(P>0.05)；4.灰度扫描结果提示：盐水组和溶剂组，从0 min到150 min，灰度值逐渐升高，150 min明显高于0 min组(P0.05);在100 min和150 min时，姜黄素中、高浓度组灰度值较溶剂组和盐水组下降明显，具有显著性差异(P<0.05)。结论 姜黄素预处理能够减少干热环境大鼠骨骼肌从红肌转化为白肌的数量，对骨骼肌线粒体的减少具有一定的抑制作用，提示姜黄素预处理可能在一定程度上保护了干热环境骨骼肌线粒体的稳定性，推测其对于干热环境下劳力型热射病并发的横纹肌溶解及继发的多脏器功能障碍可能具有一定的抑制作用。

The Changes of Histopathology and Ultramicrostructure of Skeletal Muscle in Curcumin Pretreatment Rats Under Dry Heat Environment

Objective To observe the changes of histopathology and ultramicrostrcture of skeletal muscle of curcumin pretreatment rats in the dry-heat environment. Method 200 male rats were randomly devided into 5 groups (n=40):Saline group, solvent group, low dose curcumin pretreatment group, medium dose curcumin pretreatment group, high dose curcumin pretreatment group. All groups were given a isometric gavage for 7 days.At the 8thday,all groups were transferred to the Simulated Climate Cabin for Special Enviroment of Northwest of China with the setting environment: temperature (41±0.5)℃, relative humidity(10±1)%. At the time of 0th min,50th min,100th min,150th min, 10 rats per group were gotten out from the cabin and anesthettized for collecting inferior vena cava blood for the determination of myoglobin, musculi biceps femoris were harvested and fixed in formalin for HE staining and pathological observation by optical microscope. Selected randomly from 5 field of view to measure gray scale of muscle under 10×10 microscope len. At 50th min and 150th min, the 1 mm×1 mm×1 mm tissue of rat musculi biceps femoris of saline group and high dose curcumin pretreatment group were fixed in osmium acid and used for transmission electron microscope observation,respectively. Result 1. The observation result under optical microscope showed: The color of part of muscle fiber of saline group and high dose curcumin pretreatment group fade and pale area gradually increased with the prolonging time in dry heat environment. Saline group fading region gradually fades to white, however, high dose curcumin pretreatment group pales reddish color; In addition, the number of fading muscle fibers gradually increased with time, especially in the saline group.2. Transmission electron microscopy showed that the mitochondria decreased as the main histological change in the dry heat environment, the change in the high dose curcumin pretreatment group was less than that in the saline group. The mitochondrial heap can be seen as a sign of proliferation in the high dose curcumin pretreatment group. 3.There were no significant change in the content of myoglobin in the blood of each group in the dry heat environment (P>0.05). 4.Grey scaning indicated: The greys in saline group and solvent group from were increased from 0 min to 150 min, and the 150 min group significantly higher than that of the 0 min group(P 0.05);in 100 min and 150 min, the greys in high dose and medium dose curcumin groups were lower thant that of saline and solvent group, there were significant differenc(P<0.05). Conclusion Curcumin pretreatment can decrease the number of the red muscle transformed into white muscle in rat skeletal muscle under dry heat environment, and can inhibite the reduce of the mitochondria in muscle fiber, which indicated that curcumin pretreatment can exert protective effects on the stability of the mitochondria in muscle fiber under dry heat environment, we speculate that curumin pretreatment can inhibite the rhabdomyolysis in exertional heat stoke and the secondary multiple organ dysfunction syndrome (MODS).