缺氧习服对冻伤大鼠骨骼肌耗氧量的影响

EFFECTS OF HYPOXIC ACCLIMATION ON OXYGEN CONSUMPTION OF SKELETAL MUSCLES IN RATS WITH FROSTBITE

目的与方法 :使用生物组织氧耗测量系统测定了常氧冻伤 (FN)、急性缺氧冻伤 (FAH)和缺氧习服缺氧冻伤(FHAC)大鼠后肢重度冻伤前后腓肠肌耗氧量的变化 ,以探讨缺氧习服加重冻伤组织损伤的机理。结果 :冻前 ,FHAC组腓肠肌耗氧量降低 2 6 .2 %。冻后 1d ,FN、FAH和FHAC组腓肠肌耗氧量为 5 .93± 0 .6 6 ,4.74± 1.87和 0 .76± 0 .39[kPa/(g·min) ],分别较各自冻前水平降低 76 .3% ,77.9%和 95 .9% ,FHAC组明显低于其余两组 ;冻后 5d三组的耗氧量分别恢复至各自冻前水平的 6 2 .8%、44 .9%和 2 8.8% ,FHAC组仍明显低于其余两组 ,提示缺氧习服冻伤后骨骼肌代谢率降低更明显 ,恢复更缓慢。结论 :缺氧习服和冻伤均使腓肠肌耗氧量明显减少 ,二者的叠加使缺氧习服大鼠冻后腓肠肌耗氧量进一步降低 。

Aim and Methods: Oxygen consumption of gastrocnemius in rats of frostbite at normoxia (FN), frostbite during acute hypoxia(FAH) and frostbite during hypoxia after hypoxic acclimation (FHAC) groups was investigated with a system of oxygen consumption measurement before and after the rats' right hind legs were frozen in order to provide theoretical data for exploring the reasons that hypoxic acclimation could aggravate tissue damage of animals wth frostbite. Results: Before freezing,oxygen consumption of gastrocnemius in rats of FHAC group decreased by 26.2%.At the first day after freezing, oxygen consumption of gastrocnemius in rats of FN,FAH and FHAC groups was 5.93±0.66, 4.74±1.87 and 0.76±0.39 [kPa/(g[DK1]·min)],and decreased by 76.3%, 77.9% and 95.9% respectively as compared with themselves before freezing, and that of FHAC group was much lower than those of FN and FAH groups. At the fifth day after freezing, oxygen consumption of gastrocnemius of the three groups returned to 62.8%, 44.9% and 28.8% of those themselves before freezing respectively, and that of FHAC group was much smaller than those of FN and FAH groups, showing that post frostbite metabolic rate of skeletal muscle of rats acclimated to hypoxia decreased further and restored much slowly.,and decreased by 76.3%, 77.9% and 95.9% respectively as compared with themselves before freezing, and that of FHAC group was much lower than those of FN and FAH groups. At the fifth day after freezing, oxygen consumption of gastrocnemius of the three groups returned to 62.8%, 44.9% and 28.8% of those themselves before freezing respectively, and that of FHAC group was much smaller than those of FN and FAH groups, showing that post frostbite metabolic rate of skeletal muscle of rats acclimated to hypoxia decreased further and restored much slowly. Conclusion: Both hypoxic acclimation and frostbite could decrease the oxygen consumption of gastrocnemius in rats, the complex of those two effects on oxygen consumption made the oxygen consumption to decrease further, suggesting that the changes in tissue metabolism could be one of the main factors that affected the degree of tissue damage and recovery.