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Korean J Parasitol > Volume 27(2):1989 > Article

Original Article
Korean J Parasitol. 1989 Jun;27(2):101-108. English.
Published online Mar 20, 1994.  http://dx.doi.org/10.3347/kjp.1989.27.2.101
Copyright © 1989 by The Korean Society for Parasitology
An experimental study on prednisolone-induced interstitial pneumonia caused by Pneumocystis carinii
D W Shin,Y H Lee and Y E Na
Department of Parasitology, College of Medicine, Chungnam National University, Taejon 301-131, Korea.

This study was performed to observe the role of Pneumocystis carinii as an etiologic agent of interstitial pneumonia in immunocompromised hosts. Total 90 male Sprague-Dawley rats, approximately 150-180 g, were used. Fifteen of them were used as control group and remaining 75 (5 groups) were as immunosuppression groups; group 1 received prednisolone (25 mg/kg twice weekly) only; group 2 prednisolone and tetracycline (75 mk/kg/day); group 3 prednisolone, tetracycline and trimethoprim-sulfamethoxazole (50-250 mg/kg/day); group 4 prednisolone and trimethoprimsulfamethoxazole; and group 5 prednisolone and griseofulvin (300 mg/kg/day) until death. The survival days of each group rat were calculated, and upon death their lungs were removed immediately and then stamp smears were prepared and stained by Giemsa or toluidine blue O. For histopathologic observation, lungs were fixed in 10% formalin, cut into sections and stained with Gomori's methenamine silver, hematoxylin-eosin, and Brown & Brenn stain. The results obtained were as follows: 1. The mean survival time of each group rat was 19.3 ± 5.2 days (group 1), 41.1 ± 14.0 days (group 2), 50.5 ± 18.4 days (group 3), 43.0 ± 22.9 days (group 4) or 21.8 ± 5.1 days (group 5). Significant differences were noted between group 1 and group 2(p less than 0.01), group 1 and group 3 (p less than 0.01), and group 1 and group 4 (p less than 0.01), which represented bacterial infections were most fatal in immunocompromised rats.


Fig. 1
Survival day of prednisolone-treated rats in each experimental (treated) group.

Fig. 2
Survival day of experimental rats accroding to the cause of death (A, B, C, D).

A : Bacterial pneumonia

B : Mixed infection (Pneumocystis carinii and bacteria)

C : Mixed infection (P. carinii and fungi)

D : P. carinii pneumonia

Fig. 3
A stamp specimen of a rat lung. The cyst wall of P. carinii stained purple (arrow). Toluidine blue O, ×1,000.

Fig. 4
A stamp specimen of a rat lung showing the intracystic body (arrow). Giemsa stain, ×1,000.

Fig. 5
P. carinii-infected rat lung. The cyst stained black (arrow). Gomori's methenamine silver stain, ×1,000.

Fig. 6
P. carinii-infected rat lung showing infiltration, alveolar septal thickening, and foamy amorphous exudate (arrow). Hematoxylin & eosin stain, ×1,000.

Fig. 7
Bacteria-infected rat lung. Gram positive bacteria stained blue, and Gram negative bacteria stained red. Brown & Brenn stain, ×400.

Fig. 8
Fungus-infected rat lung showing hyphae black. Gomori's methenamine silver stain, ×400.


Table 1
Mean survival day of rats in each experimental group

Table 2
Causes of death based on histopathological examination of the experimental rats

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