高温对大鼠离体心脏结构和功能的影响

目的：探讨高温对SD大鼠离体心脏结构和功能的影响。方法：将SD大鼠60只，体重200～250g，随机分为5组（n=12）：37．50c（对照组）、39．5℃、41．5℃、42．5℃、43．5℃组。采用langendorff离体心脏灌注模型，37．5℃平衡灌注15min后，各组在其相应的温度点灌注105min后再以37．5℃灌注15min，记录平衡15min时（基础值）和灌注末135min时的心功能指标（HR、LVEDP、LVDP、＋dp／dtmax、CF），HE染色光镜观察心肌组织学改变，透射电镜观察心肌超微结构的变化。结果：对照组和39．5℃组心功能指标、病理形态学无明显改变。41．5℃、42．5℃、43．5℃组灌注末与基础值相比，LVEDP升高（P〈0．05），HR、LVEDP、LVDP、±dp／dtmax、CF下降（P〈0．05）。与37．5℃组相比，41．5℃、42．5℃、43．5℃组灌注末LVEDP依次升高（P〈0．05），HR、LVEDP、LVDP、＋dp／dtmax、CF依次下降（P〈0．05），41．5℃以上组光镜下均见到不同程度的细胞肿胀，电镜下心肌超微结构发生不同程度的损害。结论：41．5℃以上的高温对SD大鼠离体心脏的功能和结构产生抑制和损伤作用，且随着温度的升高而加重。

Effects of high temperature on the structure and function of the isolated rat heart

Objective:To discuss the effects of high temperature on the structure and function of the isolated rat heart. Methods: Sixty adult SD rats weighing 200-250g were randomly divided into 5 groups(n=12 each): 37.5℃(the control group),39.5℃,41.5℃,42.5℃and 43.5℃(the other groups). The animals were anesthetized with intraperitoneal pentoharbital 30 mg/kg and heparinized. The hearts were excised and retrogradely perfused with K-H buffer saturated with 95% O2 and 5% CO2 at 10 kPa and 37.5℃ in Langendorff apparatus.After a 15 min stabilization period the hearts were perfused on the corresponding temperature point for 105 min,then returned to 37.5℃ for 15 min. HR,LVEDP,LVDP,±dp/dtmax and coronary flow (CF) were measured at the end of 15 min stabilization period(basic value) and at the end of 135 min (experiment value). Pathomorphological changes of myocardium of rats assayed with light microscope after hematoxylin-eosin staining and transmission electron microscope. Results: LVEDP was increased and HR,LVDP,±dp/dtmax and CF were decreased in the 41.5℃,42.5℃ and 43.5℃ groups as compared with the control group.Myocardial cells was observed swelling under the light microscope in the 41.5℃,42.5℃ and 43.5℃ groups . Under transmission electron microscopy, mitochondrion edema,vacuole degeneration and cristac breaking were found in the 41.5℃,42.5℃ and 43.5℃ groups. Conclusion:Temperatures above 41.5℃ have inhibitory and detrimental effects on the function and structure of the isolated rat heart. The higher the temperature is, the more serious the inhibition and injury become.