黑龙江立克次体感染血管内皮细胞的初步研究

Primary study on Rickettsia heilongjiangensis infection of vascular endothelial cells

目的通过黑龙江立克次体感染体外培养人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVEC)探讨其在内皮细胞内的生长规律。方法将泛影葡胺密度梯度超速离心纯化的黑龙江立克次体(HLJ-054株)感染体外培养的HUVEC,通过间接免疫荧光和扫描电镜检测与观察不同时相黑龙江立克次体在内皮细胞内的生长状况。热灭活黑龙江立克次体做平行对照。结果立克次体粘附并侵入内皮细胞,在感染后第6 h及第24 h分别为感染高峰;感染5 d后细胞内立克次体逐渐增殖,第8～9 d细胞内立克次体急剧增殖,并见细胞核内有少量立克次体,细胞出现病变,第12 d细胞内充满立克次体,大部分细胞皱缩脱落。结论黑龙江立克次体能够感染血管内皮细胞,在血管内皮细胞内不断增殖而使细胞死亡。

The Rickettsia heilongjiangensis organisms purified by Renografin renografin gradient centrifugation were ap plied to infected human umbilical vein endothelial cells （HUVEC） grown in monolayer on cover slips. Rickettsiae were exam ined by both indirect immune fluorescence assay （IFA） and scanning electron micrograph （SEM） after rickettsial infection. During the first 24 hours postinfection （ip）, two infection peaks were found at 6 and 24 hours pi, respectively. Multiplication of rickettsiae and pathological changes of host cells were observed at 5 days pi, while the amount of intracellular rickettsiae was markedly increased within 5 to 9 days pi. A few of rickettsiae were observed in the nucleus of host cells that appeared severe pathological changes within 8 to 9 days pi. Due to the overwhelming rickettsial infection, most of the infected host cells shed 12 days pi. Our results demonstrated that R. heilongjiangensis has a capability to infect vascular endothelial cells to cause vascular injury of humans.