急进不同低海拔环境对大鼠心肌的影响

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。

Myocardial injury in rats following a sudden increase of altitudes

Objective To investigate the influence of a sudden increase of altitudes (within 2500 m) in winter on cardiomyocyte
functions in rats. Methods Thirty male Wistar rats were randomly divided into groups A (55 m), B (1520 m), and C (2260 m)
and subjected to simulated conditions at the indicated altitudes in winter for 3 days. Blood gas analysis, venous blood
biochemistry, and measurements of SOD activity and myocardial concentrations of MDA and NO were performed.
Histopathological changes in the left ventricle were observed with HE staining and electron microscopy. Results Blood pH and
PCO2 did not differ significantly between the 3 groups, but PO2 and BE in groups B and C decreased significantly compared
with those in group A (P<0.01). Compared with group A, the rats in group C showed obviously increased myocardial enzymes,
MYB, Tn-I, and MDA contents (P<0.01) with significantly decreased SOD activity (P<0.05); both groups B and C showed
significantly decreased NO content in the myocardium (P<0.01). Histopathologically, the myocardial fiber in group C showed
irregular alignment, disruption, and mitochondrial expansion. Conclusion A sudden increase of altitude to 2260 m in winter
can potentially cause hypoxic cardiomyocyte damage as a result of oxidative and environmental stresses.