Abstract: Objective Objective To establish an animal model for Pneumocystis pneumonia（PCP）and to study the etiological and mo? lecular biological technology for PCP detection. Methods 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 sa? line 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 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 posi? tive 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，respective? ly. 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 Conclusions The animal model of PCP can be established by subcutaneous in? jection 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.

Key words: Pneumocystis carinii； Animal model；Etiological detection； PCR

摘要： 目的 目的 建立肺孢子菌动物模型， 并对肺孢子菌病原学和分子生物学检测技术进行研究。方法 方法 SD和Wistar大 鼠随机分为实验组和对照组， 实验组大鼠皮下注射地塞米松， 对照组皮下注射生理盐水。诱导8周后处死全部大鼠， 收 集其支气管肺泡灌洗液 （BALF） 和肺组织， 分别做涂片和肺印片， 染色后镜检。用FTA卡采集所有大鼠的BALF进行PCR 检测。对PCR产物进行测序， 利用BLAST软件将测序结果与GenBank数据库中的鼠源性肺孢子菌进行比对， 确定菌 种。结果 结果 共采集肺组织标本和BALF 各34份， 病原学检测显示实验组总感染率为29.2% （7/24）， 对照组感染率为0； 其 中SD和Wistar大鼠实验组感染率分别为25.0% （3/12） 和33.3% （4/12）， 差异无统计学意义 （P = 0.31）； 实验组SD大鼠肺印 片和BALF 肺孢子菌阳性检出率分别为25.0% （3/12） 和16.7% （2/12）， 差异无统计学意义 （P = 0.34）。实验组Wistar大鼠 肺印片和BALF 肺孢子菌阳性检出率分别33.3% （4/12） 和16.7% （2/12）， 差异无统计学意义 （P = 0.24）。用PCR方法共检 测28份大鼠BALF样本， 实验组阳性检出率为91.7% （26/28）， 对照组均为阴性。对PCR产物进行测序分析， 发现其与 GenBank 已登录的大鼠源肺孢子菌 （JX499145、 GU133622、 EF646865） 的同源性均为100%。结论 结论 通过皮下注射地塞米 松可以建立肺孢子菌动物模型， SD大鼠与Wistar大鼠在作为肺孢子菌动物模型的选择上无显著差别。在早期感染阶 段， 适宜用PCR法进行肺孢子菌检测， 病原形态学检测漏检率高。

关键词: 肺孢子菌； 动物模型； 病原检测； PCR检测