田鼠巴贝虫感染BALB/c小鼠血细胞动态变化

Dynamics of routine blood tests in BALB/c mice with Babesia microti infection

目的观察小鼠感染田鼠巴贝虫(Babesia microti)后体重、脾脏及血液细胞的变化情况。方法取田鼠巴贝虫感染种鼠外周血(虫密度为20%),腹腔接种6周龄健康BALB/c小鼠,100μL/只,并设立健康小鼠对照组。感染组小鼠于感染后0～28 d隔日尾尖采血,涂薄血片,吉氏染色后油镜下观察田鼠巴贝虫增殖情况,并分别于感染后0、7、14、21、28d测定小鼠体重、脾重,采用全自动血细胞分析仪分析小鼠血细胞。结果小鼠在感染后第1天即可在外周血中查见田鼠巴贝虫虫体,第7天染虫率最高(55%),随后感染率逐渐下降,至第28天外周血虫体镜检阴性,进入隐性感染阶段。小鼠于感染后第7天体重降至最低,随后逐渐恢复;脾脏重量在感染后第14天最重,后逐渐降低,但至第28天脾重仍高于正常组。全血细胞分析发现,感染组小鼠白细胞数量及淋巴细胞、嗜酸性粒细胞比例无明显变化,波动范围在正常小鼠参考值范围内。感染组小鼠红细胞计数、血红蛋白含量及血小板计数在感染后虫密度高峰期降至最低,后随着虫密度降低而逐渐恢复至正常水平。结论田鼠巴贝虫感染可引起小鼠体重下降、脾脏增重、红细胞及血小板数量降低,全血细胞分析仪对巴贝虫病诊断具有参考价值。

Objective To understand the changes in body weight, spleen weight and complete blood cells in BALB/c mice infected with Babesia microti. Methods For the infection group, six weeks old BALB/c mice were injected intraperitoneally with a dose of 100 μL of B. microti infected blood （20% RBC infection rate, each mouse）. For the determination of the progres- sion of B. microti infection up to 28 days of the infection, the microscopic visualization of thin blood smears of tail blood stained with Giemsa staining was performed in the infection group. The experiment was carried out at different intervals on days 0, 7, 14, 21, and 28 after the infection, respectively. The mice were sacrificed, and spleens were collected and weighed, and the body weight of the mice was also determined. The blood cells of the mice were analyzed by using Mindray BC- 5300 Vet animal automatic hematology analyzer. Results On the first day after the infection, B. microti was visualized in RBC of the infection group. The significantly highest infection rate （55%） appeared on the seventh day of the infection, and then steadily decreased; the mice attained the latent infection phase on the 28th day post-infection, when the parasite could not be visualized in the pe- ripheral blood. The mice in the infected group acquired a significantly lowest body weight on the 7th day of the infection, and then gradually returned to normal. The weight of the spleen was the significantly highest on the 14th day of the infection, and then consistently decreased. On the 28th day of infection, the spleen weight was still higher than that of the control group. There were no significant changes in the number of white blood cells （WBC）, lymphocytes, and eosinophils in the infected mice; and altered levels were all within the normal mouse reference range. The number of red blood cells, hemoglobin, and platelet count in the infected mice were decreased to the lowest level when the B. microti infection rate achieved to the highest, and then gradu- ally returned to the normal levels. Conclusions B. microti infection can cause body weight loss, splenic weight gain, and re- duction in the number of erythrocytes and platelets in whole blood of the mice. Besides, the whole blood cell analyzer has a diag- nostic significance in the identification of babesiosis.