Relationship between the burden of Pneumocystis carinii, the inflammatory reaction and lung injury in Pneumocystis carinii pneumonia.
OBJECTIVE
To study the relationship between the burden of Pneumocystis carinii (P. carinii) and the inflammatory reaction and biochemical markers in bronchoalveolar lavage fluids (BALF) in a rat model of P. carinii pneumonia (PCP).


METHODS
Clean grade 50 male Sprague-Dawley rats were immunosuppressed by a subcutaneous injection of 25 mg cortisone acetate twice a week for 8-12 weeks; the PCP model was successfully induced in 14 rats. The inflammatory reaction and biochemical markers of the activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and type IV collagenase (matrix metalloproteinases, MMP-2, MMP-9) as well as the values of total protein (TP) and albumin (ALB) in BALF between the mild burden group of P. carinii (involved alveoli < 25% per 100 alveoli, Group A) and the moderate to severe burden group (involved alveoli > or = 25% per 100 alveoli, Group B) were measured. The other six clean grade SD rats served as normal control group (Group C).


RESULTS
The total white cell count in BALF was higher in Group B [(6.8 +/- 1.7) x 10(6)/L] than in Group A [(3.8 +/- 1.2) x 10(6)/L] (P < 0.01); however, there were no differences in white cell differentiation. Assays of biochemical markers showed that ALB in BALF in Group B (0.893 +/- 0.469 g/L) was increased in comparison with Group A (0.262 +/- 0.169 g/L); it was only 0.026 +/- 0.021 g/L in Group C. The contents of TP and activities of LDH were higher in Group B (TP 1.756 +/- 0.706 g/L, LDH 2580 +/- 550 U/L) than in Group A (TP 0.784 +/- 0.553 g/L, LDH 1410 +/- 620 U/L); the values of TP and LDH were 0.063 +/- 0.020 g/L and 370 +/- 250 U/L respectively in Group C. The activity of Type IV collagenase, including MMP-2 and MMP-9, was higher in Group B than in Group A (P < 0.01) (MMP-2: 1102 +/- 169 grey value vs 459 +/- 274 grey value; MMP-9: 1218 +/- 257 grey value vs 449 +/- 225 grey value). There was no activity of Type IV collagenase in BALF of Group C. No statistically significant difference was observed in ALP between the groups B and A.


CONCLUSIONS
These results indicate that there is a significant correlation between the burden of P. carinii in lung tissues and the inflammatory reaction as well as biochemical markers of the resultant activity of lung injury.
Qu
J
J
Department of Pulmonary Medicine, Zhongshan Hospital, Shanghai Medical University, Shanghai 200032, China. jiemingc@online.sh.cn
Rong
Z
Z
He
L
L
Pan
J
J
Chen
X
X
D000418:Albumins / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology / Q000382:microbiology; D007249:Inflammation / Q000378:metabolism / Q000382:microbiology / Q000473:pathology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007958:Leukocyte Count; D008168:Lung / Q000378:metabolism / Q000382:microbiology / Q000473:pathology*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D011010:Pneumocystis / Q000254:growth & development*; D011020:Pneumonia, Pneumocystis / Q000382:microbiology*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D000418:Albumins; D011506:Proteins; D007770:L-Lactate Dehydrogenase; D000469:Alkaline Phosphatase; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9