低温海水淹溺大鼠心肌血栓素B_2与6-酮-前列腺素F_(1α)变化及与血气的关系

The changes of TXB_2 and 6-Keto-PGF_(1α) in the myocardium with relation to blood-gas after hypothermic sea water near drowning in rats

目的 探讨低温海水淹溺大鼠心肌ＴＸＢ２、６－Ｋｅｔｏ－ＰＧＦ１α及ＴＸＢ２／６－Ｋｅｔｏ－ＰＧＦ１α（Ｔ／Ｋ）与血气的关系。方法 将淹溺组大鼠置于低温（１６～１８℃）海水中，任其自由游动直至沉入水底，呼吸暂停，迅速取出置室温下观察，分别于５，１５，３０，６０，２４０，３６０ ｍｉｎ（每小组各６只）测大鼠肛温，取左心血行血气分析，取各小组４只检测心肌组织ＴＸＢ２及６－Ｋｅｔｏ－ＰＧＦ１α含量，观察Ｔ／Ｋ变化，肺组织计算干重／湿重比值（Ｄ／Ｗ），另２只光镜下观察肺脏及心脏形态改变。结果 淹溺大鼠肛温、ｐＨ、ＰａＯ２及 ６－Ｋｅｔｏ－ＰＧＦ１α明显降低，于５ｍｉｎ组降至最低点（Ｐ＜０．０１），ＰａＣＯ２及 ＴＸＢ２则明显上升，分别于５ｍｉｎ组及３０ｍｉｎ组升至最高点（Ｐ＜０．０１），Ｔ／Ｋ比值明显上升；淹溺后随离海水的时间延长，肛温、ｐＨ、ＰａＯ２及Ｐａ－ＣＯ２呈恢复趋势，心肌的ＴＸＢ２、６－Ｋｅｔｏ－ＰＧＦ１α及Ｔ／Ｋ比值则无明显改善。结论 低温海水淹溺大鼠心肌的ＴＸＢ２及６－Ｋｅｔｏ－ＰＧＦ１α含量受低温、低氧血症及酸中毒的影响，造成ＴＸＢ２增高、６－Ｋｅｔｏ－ＰＧＦ１α降低及Ｔ／Ｋ比值失衡从而使心脏功能趋于恶化。

Objective To investigate the changes of TXB2, 6-Keto-PGF1α and TXB2/6-Keto- PGF1α (T/K) in the myocardium with relation to blood-gas after hypothermic sea water near drowning in rats. Methods The rats were put into hypothermic sea water(16-18 ℃) and let swim freely; in about 15 minutes they would be near drowned and sunk to the bottom. Then, within a few seconds of breath- ing-stop, the rats were taken out of water immediately and examined under room temperature in every 5, 15, 30, 60, 240 and 360 min groups (6 in each group ) for rectal temperature and left heart blood-gas analysis(including pH, PaO2 and PaCO2 ). Besides,4 animals of each group were examined for myocar- dial TXB2 and 6-Keto-PGF1α contents with T/K ratio and also for dry weight and wet weight ratio (D/ W) of lung tissue; while other 2 animals were observed microscopically their changes in the lung and heart. Results After near drowning the rectal temperature, pH,PaO2,TXB2 and 6-Keto-PGF1α all de- creased obviously and reached lowest level in the 5 min group(P<0.01); while PaCO2 and TXB2 both increased remarkably and reached the highest level in 5 min group and 30 min group respectively. The T/K also increased significantly after near drowning. As time went by, the rectal temperature, pH, PaO2 and PaCO2 all had a tendency to recover, but TXB2, 6-Keto-PGF1α and T/K showed no obvious im- provement. Conclusions The contents of TXB2 and 6-Keto-PGF1α in the myocardium could be influ- enced by hypothermia, hypoxemia and acidosis in the experiment and lead to the increase of TXB2 and decrease of 6-Keto-PGF1α with T/K imbalance and at the same time worsen the function of heart.