Chin J Schisto Control ›› 2021, Vol. 33 ›› Issue (1): 28-.

### Study on the mechanisms of the intestinal tight?junction destruction caused by Blastocystis hominis infection in rats

LU Yun-Yu1△, PEI Pei2△, ZHANG Li-Lin1, XUE Sa1, HAN Xue1, BI Xiang-Lian1, ZHAO Hong-Ying3, LIU Deng-Yu1*, FU Xiao-Yin1*

1. 1 Department of Parasitology, School of Basic Medical Sciences, Guangxi Medical University, Nanning 530021, China; 2 Zhuhai People’s Hospital, Guangdong Province, China; 3 The People’s Hospital of Guangxi Zhuang Autonomous Region, China
• Online:2021-02-10 Published:2021-02-10

### 人芽囊原虫感染致大鼠肠道紧密连接破坏的机制研究

1. 1 广西医科大学基础医学院寄生虫学教研室（南宁530021）；2 广东省珠海市人民医院；3 广西壮族自治区人民医院
• 作者简介:卢韵宇，女，硕士研究生。研究方向：病原生物学 裴培，女，硕士研究生。研究方向：病原生物学
• 基金资助:
广西壮族自治区自然科学基金（2017GXNSFAA198124）

Abstract: Objective　To explore the mechanism of the intestinal barrier damage caused by Blastocystis hominis infections in rats. Methods　Thirty SD rats were randomly divided into the control group, and the 1?, 3?, 6? and 9?week?infection groups, of 6 rats in each group. Rats in each infection group were orally infected with B. hominis trophozoites at a density of 2 × 108 parasites per rat, and the control group was given an equal volume of phosphate buffered saline solution. The 7?hour urine samples were collected 1, 3, 6 and 9 weeks post?infection for the measurement of the intestinal permeability. Then, rats were sacrificed using the cervical dislocation method, and the cecum specimens were collected for the detection of the intestinal epithelial cell permeability. The expression of tight junction?related Occludin and Claudin?1 genes and apoptosis?related Bcl?2 and Bax genes was quantified in cecum epithelial cells using the real?time fluorescent quantitative PCR (qPCR) assay, and cell apoptosis was detected in the rat cecum using the TdT?mediated dUTP nick?end labeling (TUNEL) assay. Results　The median urinary lactolose to mannitol ratios were 0.29, 0.72, 0.44, 0.46 and 0.38 in the control group, and the 1?, 3?, 6? and 9?week?infection groups, respectively, and the difference was statistically significant (H = 12.09, P < 0.05). B. hominis invasion and epithelial injury were observed in intestinal epithelial cells of rats infected with B. hominis, and transmission electron microscopy displayed the destruction of tight junctions between intestinal epithelial cells. The relative expression of Occludin, Claudin?1, Bcl?2 and Bax genes was 1.04, 0.62, 0.71, 0.68 and 0.96; 1.03, 0.61, 0.63, 0.76 and 0.86; 1.08, 0.70, 0.75, 0.74 and 1.03; and 1.00, 1.57, 1.33, 1.35 and 1.10 in the control group and the 1?, 3?, 6? and 9?week?infection groups, respectively, and all differences were statistically significant (F = 2.86, 2.85, 3.37 and 4.45, all P values < 0.05). The median number of positive staining cells were 1.00, 13.00, 9.00, 3.50 and 1.00 in rat cecum specimens in the control group, and the 1?, 3?, 6? and 9?week?infection groups, respectively, and the difference was statistically significant (H = 22.95，P < 0.01). Conclusion　B. hominis infection may cause an increase in the rat intestinal permeability through triggering the apoptosis of intestinal epithelial cells to destroy the tight junction between intestinal epithelial cells, thereby destroying the intestinal barrier function.

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