Disstribution Of Prrsv And Its Receptors In Reproductive And Respiratory System Of Female Piglets

[Objective] To investigate the distribution and relative expression of porcinereproductive and respiratory syndrome virus(PRRSV) and its receptors, Sialoadhesin(Sn)、Vimentin、CD163and nonmuscle myosin heavy chain II-A(NMHC II-A),in reproductive andrespiratory system of female piglets.[Method] Indirect ELISA was used to detect the antibody level of PRRSV GP5and Nprotein in serum, immunofluorescent (IFC) staining was applied to observe the distribution ofPRRSV and its receptors, histopathological changes were observed throughhematoxylin-eosin (HE) staining and the relative expression of PRRSV receptors was testedby immunohistochemistry (IHC).[Results] The results of HE, IFC and IHC were described as follows:The results of HE staining:Compared with the control group, the infected lung, ovary, oviduct and uterus tissue hasdifferent levels of red blood cells infiltration and lymphatic macrophage infiltration. Also,with different degree of tissue damage that characterized by thickening of alveolar septum,follicle fall off to the follicular cavity, fiber arrangement is not neat, the tubal mucosacolumnar cells fall off and the uterus gland columnar nucleus present vacuolation.The distribution and relative expression of PRRSV were described as follows:PRRSV was not exist in the control group, but in the infectious group, the distribution ofPRRSV, mainly distributed in the macrophage nucleus of alveolar septum and type II alveolarcell membranes. PRRSV was seen on macrophage membranes of ovary Stroma; PRRSV waswidely distributed in oviduct and was seen on macrophage membranes and uterus glandcolumnar cell membranes in uterus. The espression of PRRSV in the lung and oviduct tissuewere significant difference (P <0.05) with the hightest expression in oviduct.The distribution of PRRSV receptors were described as follows:1. Sn was mainly existed on macrophage nucleus of alveolar septum both in PRRSVinfectious group and control group. It exists on macrophage membranes of lamina propria ofoviduct in the control group，also on macrophage membranes in muscular layer and mucosalepithelial cell membranes. But Sn was not seen both in ovary and uterus. 2. The distribution of CD163in the lung, ovary and oviduct tissue has no differencebetween the control group and infected group, mainly distributed on macrophage nucleus ofalveolar septum and type II alveolar cell membranes, on macrophages in the ovarian stromaand lamina propria and muscular layer of oviduct. CD163existed on macrophage membranesonly in the control group, also on uterus gland columnar cell membranes in PRRSV infectedgroup.3. Vimentin receptors were not seen in the lung of the control groups, but widelydistributed on macrophages and mucosal epithelial cell membranes in the infected tissue. Itdistributed on uterus gland columnar cell membranes, but also on macrophage membranes inthe control group and muscle cell membranes in the infected group. Vimentin was mainlyexisted on macrophage of ovarian stroma, macrophages nucleus of lamina propria andmuscular layer of oviduct both in PRRSV infectious group and control group.4. NMHC II-A receptors mainly distributed on the macrophage membranes of alveolarseptum in the control group but on the macrophage nucleus in infected group. It mainlydistributed on follicle cell membrane both in infected group and control group. In the oviducts,it widely distributed in the cilia, muscle cells and macrophages, but was not see on musclecells in infected group. NMHC II-A mainly distributed in the uterus gland columnar cellmembranes only in the infected group, also distributed in the muscle cells in the controlgroup.The expression of PRRSV receptors were described as follows:1. The expression of Vimentin in the lung were extremely significant difference betweenPRRSV infectious group and control group (P <0.01), but no difference for Sn, CD163andNMHC II-A receptors.2. The expression of CD163and Vimentin in the ovary were extremely significantdifference between PRRSV infectious group and control group (P <0.01), and significantdifference (P <0.05) for NMHC II-A receptor, but no expression for Sn.3. The expression of CD163in the oviduct tissues were extremely significant differencebetween PRRSV infectious group and control group (P <0.01), but no difference for Sn,Vimentin and NMHC II-A receptors（P>0.05）.4. The expression of NMHC II-A in the oviduct tissues were extremely significantdifference between PRRSV infectious group and control group (P <0.01), but no differencefor Sn, CD163and Vimentin（P>0.05）.[Conclusion] At present, the pathogenic mechanism of PRRSV was studied mainly fromthe immunology and molecular biology. It is first for present experiment to research itmorphology.The results revealed that Sn receptor is not necessary in the process of PRRSV infection, but have synergy; CD163receptors and Vimentin are required, the former assistPRRSV internalization and replication in the infected cells and the later is responsible for thevirus transportation from susceptible cells to non-susceptible cells; NMMHC II-is also aunnecessary receptors, but its expression has resistance effect on the PRRSV infection.According to the distribution and expression of PRRSV and its receptors in the lung, ovary,oviduct and the uterus, which combined with HE staining we suggested that the ovary isdifficult for PRRSV invasion but the uterus is susceptible to PRRSV. According to the way ofPRRSV transmission, lung is the first tissue for PRRSV infection, after that the virus isreleased and transported to ovary, oviduct and uterus tissue.