Study on the Relationship between TNF-?、NO in the Lung and Pulmonary Artery Pressure in Immature Rabbits with Meconium Aspiration / 中华围产医学杂志

ABSTRACT

Objective To study the changes of TNF-??NO in lung of immature rabbits with meconium aspiration and the relationship with right ventricular pressure. Methods (1)We established mild and severe immature rabbits model of meconium aspiration by endotracheal intubation imbuing meconium 0.6 ml/kg and 4 ml/kg. (2)We measured the right ventricular pressure by right ventricular puncture. (3)level of TNF-? in lung was measured by radioimmunoassay and that of NO was detected by Cr deoxidation. Results Meconium caused pulmonary inflammatory response which was reflected in the increase of cell counts in BALF, peaking at 24 h after instillation [WBC counts (6.06? 0.15 ) ?10 8/L,PMN counts (0.484?0.009)?10 8/L] and recovered by 72 h[(1.93?0.08)?10 8/L,(0 082?0 007)?10 8]. (2)The level of TNF-? in lung of mild group (1.41?0 15) ng/ml increased significantly comparing with control group (0 48?0.07) ng/ml, level of NO (31.9?2.4) ng/ml decreased significantly. Peaked at 16~24 h and recovered to normal by 72 h. the changes of severe group [TNF-?(1.85?0.17) ng/ml, NO(26.4?2.4) ng/ml] were significantly different from those in mild group. (3) At mild group,the right ventricular pressure began to increase at 16 h ( 19.28 ? 0.10 ) mm Hg, peaked at 24 h (26.78?0.14) mm Hg and returned to normal level by 72 h ( 14.18 ? 0.04) mm Hg. The pressure of severe group ( 32.70 ? 0.14 ) mm Hg was significantly higher than that of control and mild group. Conclusions (1)After immature rabbits aspirating meconium, there were remarkable pulmonary inflammatory responses. (2)The level of TNF-? in lung increased, and was correlated with right ventricular pressure,which revealed that MAS with PPHN could be associated with inflammatory response. (3)The level of NO decreased after meconium aspiration, and was lower at severe group. The level of NO was negatively correlated with right ventricular pressure, which indicated that the severe meconium aspiration was companied with severe damage of endotheliocyte which promoted and exacerbated PPHN.