Amarilla Shyrley Paola, Gómez-Laguna Jaime, Carrasco Librado, Rodríguez-Gómez Irene M, Caridad Y Ocerín José M, Graham Simon P, Frossard Jean-Pierre, Steinbach Falko, Salguero Francisco J
Department of Anatomy and Comparative Pathology, Faculty of Veterinary Medicine, Campus Universitario de Rabanales, Córdoba, Spain; Departament of Veterinary Pathology, Faculty of Veterinary, National University of Asunción (FCV-UNA), Paraguay.
Department of Anatomy and Comparative Pathology, Faculty of Veterinary Medicine, Campus Universitario de Rabanales, Córdoba, Spain.
Vet Microbiol. 2017 Mar;201:126-135. doi: 10.1016/j.vetmic.2016.12.040. Epub 2017 Jan 20.
Porcine reproductive and respiratory syndrome viruses (PRRSV) present a wide phenotypic and genetic diversity. Experimental infections have demonstrated viral replication, including highly pathogenic strains (HP-PRRSV), in primary lymphoid organs such as the thymus. However, studies of the bone marrow are scarce but necessary to help elucidate the immunobiology of PRRSV strains of differing virulence. In this study, whereas viral RNA was detected within the bone marrow of animals experimentally infected with both low virulent Lelystad (LV) and 215-06 PRRSV-1 strains and with the highly virulent SU1-bel strain, PRRSV positive cells were only occasionally detected in one SU1-bel infected animal. PRRSV RNA levels were associated to circulating virus with the highest levels detected in LV-infected pigs. At 3 dpi, a decrease in the proportion of haematopoietic tissue and number of erythroid cells in all infected groups was associated with an increase in TUNEL or cleaved caspase 3 labelling and higher counts of myeloid cells compared to control. The expression of IL-1α and IL-6 was elevated at the beginning of the infection in all infected animals. The expression of TNF-α was increased at the end of the study in all infected groups with respect to control. Different PRRSV-1 strains induced, presummably by indirect mechanisms and independently of viral load and strain virulence, moderate and sustained hypoplasia of erythroid cells and myeloid cell hyperplasia at early stages of infection. These changes were paralleled by a peak in the local expression of IL-1α, IL-6 and TNF-α in all infected groups.
猪繁殖与呼吸综合征病毒（PRRSV）呈现出广泛的表型和遗传多样性。实验感染已证明病毒可在胸腺等初级淋巴器官中复制，包括高致病性毒株（HP-PRRSV）。然而，关于骨髓的研究较少，但对于阐明不同毒力的PRRSV毒株的免疫生物学是必要的。在本研究中，虽然在实验感染低毒力莱利斯塔德（LV）和215-06 PRRSV-1毒株以及高毒力SU1-bel毒株的动物骨髓中检测到了病毒RNA，但仅在一只感染SU1-bel的动物中偶尔检测到PRRSV阳性细胞。PRRSV RNA水平与循环病毒相关，在LV感染的猪中检测到的水平最高。在感染后3天，与对照组相比，所有感染组造血组织比例和红系细胞数量的减少与TUNEL或裂解的半胱天冬酶3标记的增加以及髓系细胞计数的增加有关。在所有感染动物中，感染开始时IL-1α和IL-6的表达升高。在研究结束时，与对照组相比，所有感染组TNF-α的表达均增加。不同的PRRSV-1毒株在感染早期可能通过间接机制诱导，且与病毒载量和毒株毒力无关，导致红系细胞中度和持续性发育不全以及髓系细胞增生。所有感染组中IL-1α、IL-6和TNF-α的局部表达峰值与这些变化同时出现。
