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Image and Quantity Analysis of Blood-Gas in Rabbit's Artery and Na+-K+-ATPase in Their Lungs During PE-SWD Treated by HFJV
Dong MinDing YougZhang MinhuaLuo YunWang YanLiu HongDong Wendu
(Department of Pathology, Naval Medical College, Nanjing210099)
AbstractThis study was made to gain an insight into the mechanism of high-frquency jet ventilation(HFJV) treatment for the pulmonary edema after seawater drowning(PE-SWD). PaO2, PaCO2 and oxygen saturation(SaO2) of the rabbit and Na+-K+-ATPase in the rabbit's lungs in three groups--PE-SWD group(PE-SWD-G),HFJV group (HFJV-G) and control group(CG), were measured and analysed by the blood-gas analyser and computer image system. The results showed that, after 100 minutes' HFJV, the PaO2, SaO2 and the activity of Na+-K+-ATPase in the lung capillary endothelial cells in HFJV-G were significantly higher than those in PE-SWD-G(P＜0.01 or P＜0.05). Three parameters of Na+-K+-TAPase(G1, D1 and D2) in HFJV-G almost returned to their values in CG. The authors suggest that the increase of PaO2 and SaO2 in the rabbit's artery blood in HFJV-G is closely related to the rehabilitation of Na+-K+-ATPase activity in the lungs after HFJV. the mechanism of successful HFJV treatment for PE-SWD is that HFJV can better correct hypoxemia and improve the rehabilitation of Na+-K+-ATPase activity in the rabbit's lungs.
Key wordsHigh-frequency jet ventilationPulmonary edemaSeawater drowningBlood-gasNa+-K+-ATPase
1引言
高频喷射通气(High-Frequencey jet ventilation, HFJV)治疗海水淹溺肺水肿(Pulmonary ede-ma after seawater drowning, PE-SWD)血气和肺内Na+-K+-ATPase的研究，文献未见报导。本文旨在观察PE-SWD经HFJV治疗后兔动脉氧分压(PaO2)、二氧化碳分压(PaCO2)、血氧饱和度(Oxygen saturation, SaO2)和肺内Na+-K+-ATPase的变化特点和规律，探讨其变化机理。为临床应用HFJV治疗PE-SWD提供科学依据。
2材料和方法
选用新西兰兔24只(由江苏省农科院动物实验中心提供)，体重为2.49±0.17 kg(±s)。随机分为HFJV治疗组(HFJV group, HFJV-G)10只，未通气PE-SWD组(PE-SWD group，PE-SWD-G)14只。海水取自东经120.3°，北纬36.1°胶洲湾海域，含盐度为3.0～3.5%。
2.1模型复制
20%氨基甲酸乙酯(1.0 g/kg)耳缘静脉注射麻醉，仰卧固定于兔台上。气管切开插入“Y”型玻璃套管，用10 ml注射器连接20 cm塑料导管，将导管插入“Y”型玻璃套管内。快速向兔肺内灌入海水4 ml/kg，1 min内灌完［1］。复制出PE-SWD动物模型，连续观察120 min。
2.2HFJV治疗
HFJV-G在灌海水后20 min，用KR-Ⅲ(MC)型高频喷射呼吸机进行通气治疗。喷嘴固定在气管套管内2.0 cm深处，通气频率为180～200次/min，通气压力为0.15 kg/cm2，连续通气治疗100 min。HFJV-G除进行通气治疗外，其它实验程序和条件与PE-SWD完全相同。
2.3血气检测
两组中的每只兔在灌海水前及灌海水后不同时期，分别由股动脉取血0.5 ml，用丹麦产ABL-Ⅲ型血气酸碱分析仪对PaO2、PaCO2和SaO2进行定量检测。
2.4肺毛细血管内皮细胞Na+-K+-ATPase定量测量
2.4.1酶细胞化学反应灌注海水后120 min，PE-SWD-G和HFJV-G中兔由耳缘静脉注入3.0%戊巴比妥钠(150 mg/kg)麻醉处死。另取4只正常兔按照同样方法处死作为对照组(Control group, CG)。三组分别开胸从两肺下叶背侧取材。用2.0%多聚甲醛-0.5%戊二醛固定液固定1 h，切成0.1 mm厚的薄片，进行Na+-K+-ATPase酶反应。用1.0%钅我酸后固定1 h，EPON812包埋，LKB超薄切片机切片，不进行电子染色，直接在Hitachi-H300型电镜下观察。
2.4.2图像定量测量方法酶反应电镜底片直接用XY-540型彩色图像分析系统进行定量分析。在毛细血管酶反应阳性部位由计算机控制，自动开出测量窗口128×128象素点。在此窗口下每组测量36次，采用自行编制的专用软件，对兔肺毛细血管内皮细胞Na+-K+-ATPase 8项参数进行定量测量［2］。参数分别为：(1)酶阳性反应面积(Area of enzyme positive reaction, A1)；(2)酶阴性反应面积(Area of enzyme negative reaction, A2)；(3)酶阳性反应区平均灰度(Average grey of positive reaction area of enzyme, G1)；(4)酶阴性反应区平均灰度(Average grey of negative reaction area of enzyme, G2)；(5)酶阳性反应区最大灰度(Maximum grey of positive reaction area of enzyme, G4)；(6)酶阳性反应区灰度范围(Grey range of positive reaction area of enzyme, G6)；(7)酶阳性反应区积分光密度(Integral luminosity of positive reaction area of enzyme, D1)；(8)酶阳性反应区光密度(对数值)(Luminosity of positive reaction area of enzyme, D2)。上述参数均由图像分析仪自动测量，由计算机对各组参数进行F检验。若两组参数方差缺乏齐性，用t′检验，反之则用t检验。
3结果
3.1高频喷射通气对兔动脉血气的影响
灌注海水后10 min，PE-SWD-G和HFJV-G的PaO2和SaO2迅速降低，PaCO2明显升高。经过HFJV治疗100 min后，HFJV-G的PaO2和SaO2比PE-SWD-G明显升高(P＜0.01或P＜0.05)，并且两组中的PaCo2均显著降低(见表1)。
3.2兔肺Na+-K+-ATPase图像定量测定结果
Na+-K+-ATPase主要定位于兔肺毛细血管内皮细胞，CG、PE-SWD-G和HFJV-G三组中该酶定位分布无显著差异。PE-SWD-G兔肺内Na+-K+-ATPase的A1、D1和D3 3项参数明显低于CG，而A2、G1、G2和G44项参数则明显高于CG(P＜0.01)。应用HFJV治疗后，HFJV-G中的上述参数明显改善，有的参数甚至恢复到接近于CG(见表2)。图像分析仪灰度级为0～255级，酶阳性反应越强，测量的灰度值就越小，反之则灰度值就越大［2］。
4讨论
灌注海水后10 min，PE-SWD-G和HFJV-G两组动物出现呼吸困难，呼吸频率明显增加，两肺布满湿口罗音，气管内溢出泡沫状液体。PaO2和SaO2迅速下降，PaCO2显著升高，紫绀明显，呈现出严重的进行性低氧血症［1］。上述变化表明海水淹溺后发生了肺水肿，兔肺遭受到严重的损害［3］。
表1PaO2、PaCO2和SaO2在海水淹溺肺水肿组和高频率射通气组中的变化
Table 1Change of PaO2,PaCo2 and SaO2 in PE-SWD-G and HFJV-G (
