![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
Infectious bursal disease virus (IBDV) can cause a highly contagious disease, resulting in severe damage to the immune system that causes immunosuppression in young chickens. Both spleen and thymus are important immune organs, which play a key role in eliciting protective immune responses. However, the effects of very virulent IBDV (vvIBDV) strain LJ-5 infection on chicken spleen and thymus are still unknown. In the present study, three-week-old specific pathogen-free (SPF) chickens were infected with vvIBDV for one to five days. The vvIBDV infection significantly increased the spleen index and decreased the thymus index.
Microscopic analysis indicated necrosis, depletion of the lymphoid cells and complete loss of structural integrity in spleen and thymus. Ultrastructural analysis displayed mitochondrial and nuclear damage, including mitochondrial cristae breaks, and deformation of nuclear membrane in vvIBDV-infected spleen and thymus tissues. Cytokine levels increased in the spleen and thymus after IBDV infection, promoting inflammation and causing an inflammatory imbalance. Moreover, the mRNA expression of apoptosis-related genes was significantly upregulated in the vvIBDV infection group compared to in the control group. Meanwhile, the mRNA expression of mitochondrial dynamics was altered in the spleen and thymus of vvIBDV-infected chickens. These results suggested that vvIBDV infection triggers an imbalance of inflammatory cytokines, and apoptosis in the spleen and thymus, resulting in immune injury in chickens. This study offered basic data for the further study of vvIBDV pathogenesis.
GRAPHICAL ABSTRACT
Disclaimer
As a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.Acknowledgements
We would like to thank the Harbin Institute of Veterinary Medicine for supplying us the specific pathogen-free chickens.
Funding
This work is supported by Natural Science Foundation of Shandong Province [No. ZR2022QC116].
Authors’ contributions
Weiye Liu designed and conducted research experiments. Xuewei Huang prepared the spleen and thymus for the experiments. Weiye Liu performed qRT-PCR and sorted out the experimental results, Xuewei Huang analyzed the data and wrote the paper. All authors read and approved the final manuscript.
Declaration of competing interest
The authors have no conflicts of interest to declare.
Ethics approval and consent to participate
We obtained informed consent from the Harbin Institute of Veterinary Medicine (the animal provider) in the study. Animal experiments were carried out in accordance with the recommendations in the institutional and national guidelines for animal care and use. The protocol was approved by the Committee on the Ethics of Animal Experiments of Northeast Agricultural University, Harbin, China (2016NEFU-315, 13 April 2017).
| Abbreviations | ||
| IBDV | = | Infectious bursal disease virus |
| vvIBDV | = | Very virulent IBDV |
| SPF | = | Specific pathogen-free |
| BF | = | Bursa of Fabricius |
| RT-PCR | = | Real time polymerase chain reaction |
| Drp1 | = | Dynamin-related protein 1 |
| Mff | = | Mitochondrial fission factor |
| Mfn1 | = | Mitofusin 1 |
| Mfn2 | = | Mitofusin 2 |
| Opa1 | = | Optic atrophy protein 1 |