急性缺氧和缺氧习服对鼠足冻伤组织存活面积的影响

EFFECTS OF ACUTE EXPOSURE TO HYPOXIA AND HYPOXIC ACCLIMATION ON SURVIVAL AREA OF FROSTBITTEN TISSUES IN RATS

本工作观察了急性缺氧和缺氧习服对Ｗｉｓｔａｒ大鼠右后足冻伤组织存活面积（ｔｉｓｓｕｅｓｕｒｖｉｖａｌａｒｅａ，ＴＳＡ）的影响。急性缺氧冻伤组和平原冻伤组大鼠冻足ＴＳＡ分别为５７．６８％、６０．２５％（－１５℃冻伤）和６７．７７％、６６．８８％（－２０℃冻伤），损伤程度基本相同（Ｐ＞０．０５），表明大鼠模拟６０００ｍ高度急性缺氧８ｈ不加重冻伤引起的组织损伤。大鼠模拟６０００ｍ高度减压缺氧习服１４ｄ或２８ｄ后再作－１５℃或－２０℃冻伤，冻足ＴＳＡ仅为１４．８４％－－２３．９１％，明显少于急性缺氧冻伤组（Ｐ＜０．００１），提示缺氧习服加重高原冻伤引起的组织损伤。在缺氧习服４周内，缺氧习服对冻伤组织损伤程度的影响只与缺氧习服是否形成有关，而与习服时间长短无关。

Male Wistar rats weighing l80-220g were randomly divided into three groups :frostbite atnormoxia (FN) group, frostbite during acute hypoxia(FAH) group and frostbite during hypoxiaafter acclimation(FHAC)group.Their right hind feet were immersed in 95% alcohol at-25℃。After tissue temperature of feet reached,-15℃(-15℃ frostbite model)or-20℃(-20℃ frostbitemodel),the feet remained in-25℃ 95% alcohol for another 2 min and were then rewarmed in awater bath at 20℃ .2 weeks later, the tissue survival area(TSA) of frostbitten feet wasdetermined.The TSA of FN group and FAH group were 57.68%,60.25 %(-15℃ model)and67.77%,66.88%(-20℃ model) respectively.It suggests that acute hypoxia at 6 000m for 8h cannot aggravate the extent of damage. The TSA of FHAC group was l4.84%-23.9l %, much lessthan that of FAH group. This indicated that hypoxic acclimation at 6 000m for l4 or 28 consecutive days worsened the frostbite damage at high altitude and the extent of damage was indepen-dent of the duration of acclimation within 4 weeks.The possible causative factors are discussed.