卡氏肺孢子虫虫体负荷与肺损伤的关系研究

THE STUDY ON RELATIONSHIP BETWEEN THE BURDEN OF PNEUMOCYSTIS CARINII AND LUNG INJURY

为研究卡氏肺孢子虫 (Pneumocystis carinii,PC)虫体负荷与肺损伤的关系 ,采用清洁级 Sprague- Dawley(SD)大鼠 (5 0只 )每周两次皮下注射醋酸可的松 ,连续 8～ 12 wk,建立卡氏肺孢子虫肺炎 (PCP)模型。共计 14只大鼠 PCP诱导成功。测定支气管肺泡灌洗液 (BAL F)细胞计数及分类、总蛋白 (TP)、白蛋白 (AL B)、碱性磷酸酶(AL P)、乳酸脱氢酶 (L DH)、 型胶原酶 (MMP- 2、MMP- 9)等肺损伤的活性指标。并根据病理组织观察计数虫体累及肺泡数多少 ,将 PC虫体负荷分为轻度组 (每 10 0个肺泡中被虫体累及肺泡数 <2 5 % ,A组 ,n=6 ,)和中重度组(每 10 0个肺泡中被虫体累及肺泡数≥ 2 5 % ,B组 ,n=8) ,比较 PC虫体负荷与肺损伤的关系。 6只清洁级 SD大鼠作为正常对照组 (C组 )。结果在 PC虫体负荷中重度组的 BAL F中白细胞总数 (6 .8× 10 6 /L± 1.7× 10 6 /L)较轻度组 (3.8× 10 6 /L± 1.2× 10 6 /L)明显增加 ,但分类差异不明显。中重度组 BAL F中 AL B为 (892 .7± 46 8.9) μg/ml,较轻度组的 (2 6 2 .2± 16 9.3) μg/ml明显为高 (P<0 .0 1) ;正常对照组仅为 (2 6 .3± 2 1.0 ) μg/ml。中重度组 TP为(175 5 .6± 70 5 .6 ) μg/m l、L DH为 (2 5 .8± 5 .5 ) U/dl,显著高于轻度组 [TP(783.5± 5 5 3.0 )

To study the relationship between the burden of Pneumocystis carinii (P.C) and lung injury. 50 male clean grade Sprague Dawley rats were immunosuppressed by subcutaneous injection of 25 mg cortisone acetate twice a week for 8-12 weeks. P. carinii pneumonia(PCP) were induced successfully in 14 rats. The inflammatory reaction and biochemical markers of resultant activities of lactate dehydrogenase(LDH), alkaline phosphatase (ALP) and type Ⅳ collagenase(matrix metalloproteinases, MMP 2, MMP 9) as well as the contents of total protein (TP), albumen(ALB) in bronchoalveolar lavage fluids between the mild burden group of P.C (involved alveoli per 100 alveoli < 25%, group A) and moderate to severe group (involved alveoli per 100 alveoli ≥25%, group B) were measured for evaluating the relationship between the burden of P.C and lung injury. The other six clean grade SD rats were set as normal control group (group C ). The results showed that the total white blood cell count in BALF in group B were higher than those in group A ( P <0.01), however, there was no difference in white cell differentiate. Assays of biochemical markers show that ALB in BALF in group B [(892.7±468.9) μg/ml] was increased in comparison with group A [(262.2±169.3) μg/ml]; there was only (26.3±21.0) μg/ml in group C. The contents of TP and activities of LDH in group B [TP(1 755.6±705.6)μg/ml , LDH(25.8±5.5) U/dl] were higher than that in group A [TP(783.5±553.0) μg/ml, LDH (14.1±6.2) U/dl]; the TP and LDH were (62.8±19.6) μg/ml and (3.7±2.5) U/dl respectively in group C. The activities of Type Ⅳ collagenase, including MMP 2, MMP 9, were higher in group B than those seen in group A ( P <0.01) (MMP 2: 1 102±169 brightness values vs 459±274 brightness values; MMP 9: 1218±257 brightness values vs 449±225 brightness values), there was no activity of Type Ⅳ collagenase in BALF of group C. There was no statically difference in ALP between the group B and group A. These results indicate that there are obvious lung injury in PCP and the close relation between the burden of P. carinii and lung injury.