Newcastle disease virus induces testicular damage and disrupts steroidogenesis in specific pathogen free roosters

Abstract

Newcastle disease (ND), which is caused by Newcastle disease virus (NDV), can cause heavy economic losses to the poultry industry worldwide. It is characterised by extensive pathologies of the digestive, respiratory, and nervous systems and can cause severe damage to the reproductive system of egg-laying hens. However, it is unknown whether NDV replicates in the male reproductive system of chickens and induces any pathologies. In this study, we selected a representative strain (i.e. ZJ1) of the most common genotype (i.e. VII) of NDV to investigate whether NDV can induce histological, hormonal, and inflammatory responses in the testes of specific pathogen free (SPF) roosters. NDV infection increased the expression of toll like receptor TLR3, TLR7, MDA5, IFN-α, IFN-β, IFN-γ, IL-8, and CXCLi1 in the testes of NDV-infected roosters at 5 days post-infection (dpi). Severe histological changes, including decrease in the number of Sertoli cells and individualized, shrunken spermatogonia with pyknotic nuclei, were observed at 3 dpi. At 5 dpi, the spermatogenic columns were disorganized, and there were fewer cells, which were replaced by necrotic cells, lipid vacuoles, and proteinaceous homogenous material. A significant decrease in the plasma concentrations of testosterone and luteinizing hormone (LH) and the mRNA expression of their receptors in the testes, steroidogenic acute regulatory protein, cytochrome P450 side-chain cleavage enzyme, and 3β-hydroxysteroid dehydrogenase in the NDVinfected group was observed relative to those in the control group (P < 0.05). Collectively, these results indicate that NDV infection induces a severe inflammatory response and histological changes, which decrease the steroidogenesis.

Newcastle Disease Virus Induced Pathologies Severely Affect the Exocrine and Endocrine Functions of the Pancreas in Chickens

“…The virus copy numbers were detected from the pancreas, as described previously [ 12 ]. Briefly, the ZJ1 strain was grown in 10-day-old SPF-embryonated eggs, and allantoic fluid was collected after 60 h of infection.…”

“…About 1 μg RNA extracted from the pancreas samples was reverse transcribed to cDNA with HiScript II (Catalog Number: R233; Vazyme Biotech Co., Ltd., China), and quantitative PCR was performed with the SYBR Premix (Dongsheng Biotech, China). Virus copy numbers were calculated using the standard curve [ 12 ].…”

“…ND mainly affects the digestive, respiratory, and nervous systems [ 8 , 9 , 10 , 11 ] but is not limited to these organs. NDV-induced pathologies and replication have been noted in the spleen, liver, bursa of Fabricius, heart, and reproductive system [ 12 , 13 , 14 , 15 , 16 ]. Previous outbreaks of NDV in vaccinated and nonvaccinated poultry reported the involvement of the pancreas [ 15 , 17 , 18 ].…”

Newcastle Disease Virus Induced Pathologies Severely Affect the Exocrine and Endocrine Functions of the Pancreas in Chickens

“…The virus copy numbers were detected from the pancreas as described previously [9]. Briefly, the ZJ1 strain was grown in 10-day-old SPF embryonated eggs and allantoic fluid was collected after 60 h of infection.…”

Newcastle Disease Virus Induced Pathologies Severely Affect the Exocrine and Endocrine Functions of Pancreas in Chickens

“…ND mainly affect the digestive, respiratory and nervous system [5][6][7][8], but not limited to these organs. AOAV-1 induced pathologies and replication had been noted in spleen, liver, bursa of Fabricious, heart, reproductive system [9][10][11][12][13]. Previous outbreaks of AOAV-1 in vaccinated as well as non-vaccinated poultry had reported the involvement of pancreas [12,14,15].…”