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目的联合血气、血液生化及组织形态变化探讨在冬季急进不同海拔(2500 m以内)环境下对大鼠心肌的影响。方法实验Wistar雄性大鼠30只,分为A组(海拔55 m)、B组(海拔1520 m)及C组(海拔2260 m)三组。正常饮水喂食,在各海拔处标准饲养3 d,动脉血测定血气,静脉血做生化检测,取心肌组织用比色法测定丙二醛(MDA)、超氧化物歧化酶(SOD)、一氧化氮(NO),用细胞化学HE染色法及电镜观察左心室病理结构的改变。结果各组血气pH、PCO2均无差异,但C组均较A组PO2及BE明显下降(P<0.05);心肌酶谱、MYO及Tn-I值C组较A组明显增加(P<0.01);与A组相比C组心肌组织氧化应激的MDA明显增加(P<0.01),SOD明显下降(P<0.05),B、C组NO均较A组明显减少(P<0.01);病理切片结果显示C组大鼠心肌细胞排列紊乱,肌纤维溶解断裂;电镜显示C组有部分肌丝断裂,少量线粒体扩张。结论在冬季急进低海拔2260 m处大鼠心肌有一定程度的损伤,其为高原低氧的氧化应激及环境变化动物应激所造成的综合结果。
Objective To study the effects of blood gas, blood biochemistry and histomorphology on the myocardium of rats under different altitude (2500 m) in winter. Methods Thirty Wistar male rats were divided into three groups: group A (55 m above sea level), group B (1520 m above sea level) and group C (sea level 2260 m). Normal drinking water was fed at each altitude for 3 days. The arterial blood was determined for blood gas and venous blood for biochemical detection. The myocardial tissue was taken for determination of malondialdehyde (MDA), superoxide dismutase (SOD) Nitric oxide (NO) was detected by cytochemistry staining and electron microscopy. Results There was no difference between the two groups in blood gas pH and PCO2, but the levels of PO2 and BE in group C were significantly lower than those in group A (P <0.05). The levels of myocardial enzymes, MYO and Tn-I in group C were significantly higher than those in group A (P <0.01) Compared with group A, the MDA level in myocardial tissue of group C increased significantly (P <0.01) and the level of SOD decreased (P <0.05). The level of NO in group B and C decreased significantly compared with group A (P <0.01). The results of pathology showed that the myocardial cells in group C were disordered and the muscle fibers were dissolved and broken. Electron microscopy showed some myofilaments were broken and a few mitochondria were dilated in group C. Conclusions Myocardial injury in rats with a low altitude of 2260 m in winter can be attributed to a certain degree of damage, which is caused by the oxidative stress of plateau hypoxia and animal stress caused by environmental changes.