鸭坦布苏病毒引起不同日龄鸭血-脾屏障及周围组织病理变化的比较研究

A comparative study on the blood-spleen barrier and pathological variation of surrounding tissues caused by duck Tembusu virus infecting ducks at different ages

为了比较鸭坦布苏病毒(duck Tembusu virus,DTMUV)感染7日龄与6月龄鸭引起血-脾屏障(blood-spleen barrier,BSB)及周围组织病理变化的差异,选用DTMUV XZ-2012纯化毒株,以105 TCID50剂量腿部肌肉攻毒,感染后3、7、11 d(3、7、11 dpi)采集脾脏并通过光镜和电镜观察其病理组织学变化。结果显示:对照组7日龄鸭脾脏及BSB发育不成熟。HE染色结果表明,3 dpi,2个年龄组鸭脾脏红、白髓界限模糊,椭球和椭球周围淋巴鞘(periellipsoidal lymphatic sheaths,PELS)内细胞坏死,7日龄鸭脾脏损伤更严重;7 dpi,7日龄鸭脾脏椭球周围仍有空泡变性的现象,但6月龄鸭脾脏开始恢复;11 dpi,7日龄鸭脾脏椭球和PELS结构仍不清晰,而6月龄鸭脾脏结构基本正常。免疫组化结果表明,3~11 dpi,7日龄鸭脾脏内DTMUV阳性反应比6月龄鸭强。网状纤维染色结果显示,3 dpi,DTMUV引起7日龄鸭脾脏椭球壁、PELS区域网状纤维大量减少,比6月龄鸭严重;7~11 dpi,7日龄鸭BSB网状纤维的恢复比6月龄鸭慢。超微结构结果表明,3 dpi,7日龄鸭脾脏内细胞核膜皱缩及细胞水肿都比6月龄鸭严重;7 dpi,DTMUV诱导2个年龄组鸭脾脏内细胞凋亡。11 dpi,7日龄鸭脾脏内部分细胞仍有脂质。结论:与6月龄鸭相比,DTMUV对BSB未发育成熟的7日龄鸭BSB及周围组织的损伤更严重,且7日龄鸭脾脏的恢复较慢。DTMUV可在体内诱导鸭脾脏内细胞凋亡,这为DTMUV致病机制的研究提供支持。

The aim of this study was to compare the pathological changes of the blood-spleen barrier(BSB)and the surrounding tissues caused by duck Tembusu virus(DTMUV)infecting 7-day and 6-month old ducks.A 105 TCID50 dose of the DTMUV XZ-2012 strain was intramuscularly injected into the ducks.Then,their spleens were collected at 3,7,and 11 days post-infection(dpi),and the spleen samples were analyzed by light and transmission electron microscopy.The results of the control groups showed that the spleen and BSB of the 7-day-old ducks were immature.The results of HE staining showed that,at 3 dpi,the boundaries of red and white pulps were unclear,and there was necrocytosis in the ellipsoids and periellipsoidal lymphatic sheaths(PELS)in both age groups,but the lesions in the 7-day-old ducks were more serious.At 7 dpi,vacuolar degeneration was observed around the ellipsoid in the spleens of the 7-day-old ducks,but the spleens of the 6-month-old ducks began to recover.At 11 dpi,the structure of the ellipsoid and PELS in the spleens of the 7-day-old ducks was still unclear while that of the 6-month-old ducks was generally normal.The results of IHC showed that the positive reactions of DTMUV in the spleens of the 7-day-old ducks were stronger than those of the 6-month-old ducks during 3-11 dpi.The results of reticular fiber staining showed that,at 3 dpi,DTMUV caused high decrease in reticular fibers in the area of the ellipsoidal wall and PELS in the spleen of the 7-day-old ducks,which were more serious than those in the 6-month-old ducks.During 7-11 dpi,the recovery of BSB reticular fiber of the 7-day-old ducks was slower than that of the 6-month-old ducks.The ultrastructural results showed that,at 3 dpi,nuclear membrane shrinkage and edema in the cells of in the spleens of the 7-day-old ducks were more serious than those of the 6-month-old ducks.At 7 dpi,DTMUV induced apoptosis of splenic cells in both age groups.At 11 dpi,there was lipid in the cells of the spleens of the 7-day-old ducks.In conclusion:compared with those of the 6-month-old ducks,the damages of BSB and surrounding tissues caused by DTMUV infecting the7-day-old ducks with immature BSB were more serious and the recovery of the spleens of the 7-day-old ducks were slower.DTMUV induced apoptosis of splenic cells in vivo.Our results provided support for research on the pathogenic mechanism of DTMUV.