猪HEV实验感染SD大鼠的研究

Experimental infection of SD rats with swine hepatitis E virus(HEV)

目的探索SD大鼠对猪HEV的易感性。方法 22只SD大鼠,随机分为4组,每组均设一只对照。前两组实验鼠分别经尾静脉注射0.6×102GE和1.2×102GE猪HEV 4型病毒液(病毒滴度为102GE/mL),其余两组实验鼠分别经灌胃途径给予0.6×102GE和1.2×102GE病毒液。每组的对照鼠均以相应途径给予相应剂量的PBS。在注射前及注射后分别采集鼠血清和粪便标本,用RT-nPCR法检测HEV RNA及ELISA法检测血清抗-HEV总抗体;且当血清ALT水平升高后取鼠肝组织通过光镜和电镜检查病理学变化。结果静脉注射大剂量病毒组的4只SD大鼠在感染2周后血清ALT明显升高,其中3只肝组织病理学检查出现轻微的非特异性炎症反应,有1只鼠出现抗-HEV抗体阳转;其他组的鼠感染后未见异常改变。所有血清标本和粪便标本均未检测出HEV RNA。结论猪HEV可能会跨种系传播感染SD大鼠但易感性较低且需较大的感染剂量。

To study the susceptibility of SD rats to swine HEV infection,22 healthy SD rats were randomly divided into 4 groups with one rat as control in each group.The rats in group 1 and 2 were inoculated with 0.6×102 GE and 1.2×102 GE of swine HEV viral suspension（virus load： 102 GE/mL） via caudal vein respectively.The other two groups were administrated with 0.6×102 GE and 1.2×102 GE viral suspension via gastric perfusion respectively.The control rats in each group were administrated with the corresponding dose of PBS via the matching route.The stool and sera specimens were collected pre-administration and post-administration respectively,and were detected for HEV RNA by the method of RT-nPCR,and for anti-HEV antibody by ELISA.The liver tissues were examined by both light microscopy and electron microscopy for the detection of pathological changes.Elevated ALT level was observed two weeks post-infection in four rats with high-dose inoculation of viral suspension.Three of them were found slight inflammatory changes in liver tissues.The seroconversion of anti-HEV antibody was occurred to one of them.The rats in other groups were not observed abnormal changes after infection.HEV RNA was not detected in all stool and serum samples.Based on these results,high dosage inoculation of swine HEV could possibly cause cross-species transmission to SD rats but with low susceptibility.