鸭坦布苏病毒自然感染的肝脏病理组织学观察

The histopathologic changes of the liver from the ducks naturally infected with Tembusu virus

对采集于广州市白云区蚌湖镇的疑似坦布苏病毒感染的蛋鸭病例进行剖解,观察大体器官病变。取肝脏组织首先进行该病毒的RT-PCR鉴定,确认自然感染该病毒后,对其肝脏进行光学和透射电镜观察。结果显示:坦布苏病毒自然感染的严重病例,剖解见肝脏肿大,色泽偏土黄,有暗红色出血斑,边缘增厚,质地变脆。光镜观察,见肝细胞索受损严重,细胞排列紊乱,胞内结构破坏,着色性下降,异嗜性白细胞浸润,在变性坏死的肝细胞周围聚集多量含铁血黄素颗粒。电镜观察发现,肝细胞严重损伤,大量肝细胞肿胀坏死,原生质外流,细胞质充满肿胀的囊泡,糖原外泄,线粒体肿胀变性;细胞核严重空泡化,核膜破裂,核质外流,出现大片的核内空白区。肝内见多量异嗜性白细胞,亦可见多量巨噬细胞和少量上皮样细胞,后二者都具有旺盛的吞噬或吞饮活动。

Presumed Tembusu virus infected ducks were collected from a duck-raising farm located in Banghu town,Baiyun district, Guang Zhou city and were slaughtrered and disected to observe the gross pathologic changes in their bodies. A special RT-PCR was conducted to determine whether the collected ducks were indeed infected with the Tembusu virus. Then the hepatic tissue samples were collected to subject to the procedures of optical microscopic and transmission electron microscopic observations. The results were as following. By naked eye observation, the suffered livers became swelling, and earth-yellow and had dark-red bleeding spots. The borders of these organs became thicker and the whole livers became fragiler. Under optical microscopic observation, we found that the liver tissue was seriously damaged, the hepatic cells were in disorderlly arrangent. The intracellular structures were seriously destroyed and their stainability was attenuated. Many heterophil leucocytes infitrated in the hepatic tissue and a lot of hemosiderin granules distributed around the destroyed hepatocytes. Transmission electron microscopic observation showed that the hepatocytes were seriously damaged, resultring in cell swelling, necrosis, protoplasma leakage, swelling vesicles and swelling mitochondria congesting in the perikaryons, glycogen leaked out of the cells, nucleus vacuolization, perinuclear membrane penetrating, karyolymph leaking, heterochromatine concentrating and euchromatine losing. By ultrastructural observation, heterophile leucocytes were frequently seen in the affected hepatic tissue. These cells were devoid of phagosomes and heterophagic vacuoles. Many macrophages and a few epithelioid cells presented in the affected hepatic tissue, most of the cells showed active phagosytosis and contained plenty of phagosomes and heterophagic vacuoles.