[Establishment of animal model for Pneumocystis carinii and study on etiological and molecular biological detection technology].
OBJECTIVE
To establish an animal model for Pneumocystis pneumonia (PCP) and to study the etiological and molecular biological technology for PCP detection.


METHODS
SD and Wistar rats were divided into experimental and control groups randomly. The animals in the experimental group were immunosuppressed by subcutaneous injection with dexamethasone 2 mg per time per rat, twice a week, while those in the control group underwent the same way of injection with physiological saline simultaneously. After the induction for 8 weeks, all the rats were killed and their bronchoalveolar lavage fluid (BALF) and lung tissues were collected for smear making and microscopic detection. Meanwhile, the BALF samples were detected by PCR, and the products were sequenced and compared with rat source PCP in GenBank.


RESULTS
A total of 34 samples of lung tissue and BALF were observed. The etiological detection showed that the infection rates of the rats in the experimental and control groups were 29.2% (7/24) and 0, respectively. In the experimental group, the infection rates of SD and Wistar rats were 25.0% (3/12) and 33.3% (4/12), respectively, and the difference between them was not statistically significant (P = 0.31). The positive detection rates of the lung smears and BALF from SD rats in the experimental group were 25.0% (3/12) and 16.7% (2/12), respectively, while those in Wistar rats in the experimental group were 33.3% (4/12) and 16.7% (2/12), respectively, and there were no statistically significant difference between them (P = 0.34, 0.24). A total of 28 samples of BALF were detected by PCR, and the positive detection rates of rats in the experimental group and control group were 91.7% (26/28) and 0, respectively. The sequence analysis of the PCR products showed that it shared 100% homology with the genes of rat source PCP in Gen Bank (JX499145, GU133622 and EF646865).


CONCLUSIONS
The animal model of PCP can be established by subcutaneous injection with dexamethasone. As animal models, there are no significant difference between SD rats and Wistar rats. PCR method is suitable for PCP detection at the early stage of infection, while etiological detection with high missing rate is not a right option.
Li-guang
LG
Tian
Lin
L
Ai
Yan-hong
YH
Chu
Xiu-ping
XP
Wu
Yu-chun
YC
Cai
Zhuo
Z
Chen
Shao-hong
SH
Chen
Jia-xu
JX
Chen
D000818:Animals; D004195:Disease Models, Animal; D008297:Male; D045363:Pneumocystis carinii / Q000235:genetics; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis* / Q000382:microbiology; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar