血清对肺表面活性物质功能的影响

Influence of serum on surfactant function

目的 探讨血清对肺表面活性物质 (PS)功能的影响。方法 用血清将PS稀释溶解配制成 2 0、4 0、6 0、8 0、10、12、2 4mg/ml的实验液体。同时作为对照将PS溶解于醋酸林格液中配成相同的浓度。用表面张力计测定实验液体的表面张力。未成熟胎兔 36只随机分为 4组 (每组 9只 ) :A组 ,经气道内注入溶解于醋酸林格液的PS 2 4mg/ml;B组 ,注入溶于血清的PS 2 4mg/ml;C组 ,注入溶于醋酸林格液的PS 4 0mg/ml;D组 ,未注入任何物质 ,进行人工通气。通气后 5、10、15、2 0min测定动物的潮气量。结果 溶解于醋酸林格液的PS浓度在 2 0mg/ml时 ,最小表面张力 (γmin)小于3 0mN/m。溶剂为血清时 ,γmin增至 30mN/m (P <0 0 1)。PS的浓度增加到 6 0mg/ml时 ,γmin降至 9 0mN/m。人工通气 2 0min时 ,A组动物的潮气量大于 15ml/kg ,而B组小于 8 0ml/kg (P <0 0 5 ) ,C组未超过 5 0ml/kg ,D组未超过 2 0ml/kg。 结论 血清明显抑制PS的功能 。

Objective To examine the influence of serum on pulmonary surfactant (PS) function.Methods Caesarean section was performed on 26-day pregnant Japanese white rabbits (full term=31 days). The pre-term rabbits weighing 20-34g were anesthetized with intraperitoneal(ip) pentobarbital sodium 0.5mg. Tracheotomy was performed. Test liquids were prepared by suspending PS in rabbit serum or acetate Ringer solution at concentration of 2.0,4.0,6.0,8.0,10,12,24 mg/ml. The surface tension of test liquids was measured by pulsating bubble technique. Test liquid 10ml/kg was instilled in the lungs of PS-deficient pre-term rabbits via tracheotomy cannula.Animals were ramdomly divided into 4 groups according to the test liquid used: group A: 24mg/ml PS suspended in acetate Ringer solution; group B: 24mg/ml PS suspended in serum; group C: 4.0mg/ml PS suspended in acetate Ringer solution; group D: nothing was instilled. Rabbits were placed in plethysmograph. Siemens-Elema ventilator was used for mechanical ventilation. PIP was set at 22.5cmH 2O, PEEP=0,respiratory rate=40 frequency/min, I:E=1:1,FiO 2=100%. Tidal volume was measured at 5,10,15,20 min after the start of mechanical ventilation.Results When concentration of PS suspended in acetate Ringer solution was 2.0 mg/ml, the minimum surface tension (γmin) was less than 3.0 mN/m; when suspended in serum, γmin was significantly higher than 30 mN/m (P<0.01). When the concentration of PS was increased to 6.0 mg/ml, γmin was reduced to less than 9.0 mN/m. Animals in group A had a mean tidal volume >15 ml/kg, but in group B the mean tidal volume was <8.0 ml/kg after 20min of mechanical ventilation.Conclusions Serum inhibits PS function and the inhibition is PS-concentration dependent.