卡氏肺孢子虫肺炎支气管肺泡灌洗液中表面活性蛋白A和D的变化

目的为进一步明确表面活性蛋白与卡氏肺孢子虫肺炎(PCP)的关系及肾上腺皮质激素对表面活性蛋白的影响.方法通过每周两次皮下注射25mg醋酸可的松8-12周建立PCP及细菌性肺炎大模型.收集支气管肺泡灌洗液(BALF),计数BALF中有核细胞数并分类,用免疫印迹法检测表面活性蛋白A(SP-A)及表面活性蛋白D(SP-D).将大分为免疫抑制组(共三组)及正常对照组.Ⅰ组:正常对照(n=6),为健康SD大;Ⅱ组:阴性对照(n=6),为注射醋酸可的松8周以上无肺部感染的大;Ⅲ组:细菌性肺炎(n=11),为注射醋酸可的松8周以上出现细菌性肺炎而未分离到其它病原体的大;Ⅳ组:PCP(n=14),为注射醋酸可的松8-12周出现PCP而未分离到其它病原体的大.结果阴性对照组BALF中细胞总数低于正常对照组(P＜0.001).PCP组BALF中细胞总数及多形核细胞(PMNs)百分数高于阴性对照组(P＜0.01),但低于细菌性肺炎组.PCP组BALF中SP-A浓度(45.1±22.1μg/ml)显著高于阴性对照组(16.2±9.9μg/ml,P＜0.05)及细菌性肺炎组(6.2±5.6μg/ml,P＜0.001).我们也发现PCP组中SP-D相对含量(24 249±4780灰度值)显著高于阴性对照组(13 384±2887,P＜0.001)及细菌性肺炎组(11 989±2750灰度值,P＜0.001).PCP中重度组SP-A、SP-D高于PCP轻度组(分别P＜0.01,P＜0.001).阴性对照组SP-A、SP-D高于正常对照组,但无统计学差别.结论卡氏肺孢子虫特异性刺激引起BALF中SP-A、SP-D浓度增加,SP-A、SP-D增加与肺内富含卡氏肺孢子虫有关,而与肾上腺皮质激素的应用无关.

Alteration of surfactant proteins A and D in bronchoalveolar lavage fluid of pneumocystis carinii pneumonia

Objective To understand the interaction between surfactant proteins and pneumocystis carinii pneumonia (PCP),and the impact of corticosteriods on surfactant proteins.Methods We established rat models of PCP and bacterial pneumonia induced by subcutaneous injection of 25mg cortisone acetate.At 8- 12 wk,the bronchoalveolar lavage fluid(BALF)of rats was collected.Total nucleated cells of BALF were counted and differentiated,and the concentrations of surfactant protein A(SP-A)and surfactant protein D(SP-D)were measured by immunoblotting assay.The rats were divided into three immunosuppressive groups and a normal control group.Group I,normal control(n = 6),consisted of healthy SD rats;group Ⅱ,negative control(n = 6),consisted of rats with cortisone acetate injection for over 8 wk without lung infection;group Ⅲ,bacterial pneumonia(n = 11),rats were injected with cortisone acetate over 8 wk that resulted in bacterial pneumonia without other pathogens isolated;and group Ⅳ,PCP(n = 14),rats with injected cortisone acetate for 8 - 12 wk and developed PCP without other pathogens isolated.Results Our results indicated that the total cell count in BALF in the negative control group was lower than that in the normal control group(P ＜ 0.001).During PCP infection,the total cell count and the percentage of polymorphonuclearcytes(PMNs)in BALF were significantly increased(P ＜ 0.01),but were lower than those in the bacterial pneumonia group.The concentration of SP-A of BALF in PCP(45.1 ± 22.1 μg/ml)was significantly increased in comparison with that in the negative control(16.2 ± 9.9 μg/ml,P ＜ 0.05)and bacterial pneumonia groups(6.2 ± 5.6 μg/ml,P ＜ 0.001).We also found that the relative content of SP-D was significantly higher in PCP(24249 ±4780 grey values)than that in the negative control (13 384 ± 2887 grey values,P ＜ 0.001)and that in bacterial pneumonia(11 989 ± 2750 grey values,P＜0.001).SP-A and SP-D were also higher in the moderate to heavy group of PCP than those seen in the mild group(P ＜ 0.01,P ＜ 0.001).SP-A and SP-D were higher in the negative control group than those in the normal control group,but there was no significant difference between the 2 groups.Conclusion These results suggest that the concentrations of SP-A and SP-D in BALF are increased by pneumocystis carinii specific stimulation,but the alteration is not related to the corticosteriod usage.