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Tk-deleted pseudorabies virus retains high pathogenicity in rats
2021
Zhang, Lirong | Ruan, Keyue | Sang, Guoju | Xu, Zhaoyang | Tong, Wu | Yu, Hai | Shan, Tongling | Gao, Fei | Li, Liwei | Kong, Ning | Tong, Guangzhi | Zheng, Hao
The pseudorabies virus (PRV) gene encoding thymidine kinase (tk) is an important virulence-associated factor. Attenuation of PRV in susceptible animals is a frequent result of tk deletion. The aim of the study was to assess the pathogenicity of tk-deleted PRV in rats. Sprague Dawley rats were infected with the tk-deleted PRV strain SuHV-1 ΔTK:247via intranasal or intramuscular inoculation. PRV loads in ten tissues from dead and euthanised rats were determined using real-time PCR. Infection with SuHV-1 ΔTK:247 could cause death in rats. The 50% lethal dose (LD₅₀) of SuHV-1 ΔTK:247 via intranasal inoculation was 10³.¹⁶ TCID₅₀ in rats. Intramuscular inoculation required a higher dose of SuHV-1 ΔTK:247 (10⁵.⁰ TCID₅₀). A high SuHV-1 ΔTK:247 titre was observed in the trigeminal ganglia or spinal cord of dead rats. The results of this study show that rats are highly susceptible to PRV infection, and tk deletion did not completely diminish the pathogenicity of PRV in rats.
Show more [+] Less [-]Acute and sub-chronic toxicity study of recombinant bovine interferon alpha in rodents
2021
Yu, Hai-Yang | Gao, Dong-Mei | Zhou, Wei | Xia, Bing-Bing | He, Zhi-Yuan | Wu, Bo | Jiang, Min-Zhi | Wang, Mingli | Zhao, Jun
Recombinant bovine interferon alpha (rBoIFN-α) has been demonstrated to have antiviral activity. However, no conduct of acute or chronic toxicity tests has been reported. Specific pathogen-free Sprague Dawley rats were administered doses at different concentrations through intraperitoneal or intravenous injection. After the administration (single for an acute toxicity test over 14 days or daily for a sub-chronic toxicity test over 30 days), the rats’ behaviour and other indicators and the degree of toxic reaction were continuously monitored. Blood was collected for haematological and serum biochemical examinations. At the end of the experiments, the rats were sacrificed for necropsy and histopathological tissue analysis. The external performance, behaviour characteristics, and changes in body temperature and body weight of the rats in each subgroup were comparable to the normal control subgroup. Except for a few cases, there were no lesions in the viscera’s pathological structures, and the blood parameters and biochemical indicators were not noticeably different from those of the control subgroup. This study suggests that rBoIFN-α seems to be safe for rats, and its use may foster the development of the cattle industry in China by protecting livestock health.
Show more [+] Less [-]Local and systemic influence of toxic levels of airborne ozone on the inflammatory response in rats
2021
Chmielewska-Krzesińska, Małgorzata | Wąsowicz, Krzysztof
Ozone is not harmful itself; however, it directly oxidises biomolecules and produces radical-dependent cytotoxicity. Exposure to ozone is by inhalation and therefore the lungs develop the main anti-inflammatory response, while ozone has an indirect impact on the other organs. This study investigated the local and systemic effects of the ozone-associated inflammatory response. Three groups each of 5 Wistar Han rats aged 6 months were exposed for 2h to airborne ozone at 0.5 ppm and a fourth identical group were unexposed controls. Sacrifice was at 3h after exposure for control rats and one experimental group and at 24 h and 48 h for the others. Lung and liver samples were evaluated for changes in expression of transforming growth factor beta 1, anti-inflammatory interleukin 10, pro-inflammatory tumour necrosis factor alpha and interleukin 1 beta and two nuclear factor kappa-light-chain-enhancer of B cells subunit genes. Total RNA was isolated from the samples in spin columns and cDNA was synthesised in an RT-PCR. Expression levels were compared to those of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and analysed statistically. All variables changed non-linearly over time comparing experimental groups to the control. Conspicuous expression changes in the subunit genes and cytokines were observed in both evaluated organs. Locally and systemically, inflammation responses to ozone inhalation include regulation of certain genes’ expression. The mechanisms are unalike in lungs and liver but ozone exerts a similar effect in both organs. A broader range of variables influential on ozone response should be studied in the future.
Show more [+] Less [-]Effects of repeated lipopolysaccharide treatment on growth performance, immune organ index, and blood parameters of Sprague-Dawley rats
2018
Zhong, Youbao | Zhang, Xianlai | Hu, Xiaofen | Li, Yong
The study was designed to investigate the effects of repeated lipopolysaccharide (LPS) treatment on growth performance, lymphoid organ indexes, and blood cells in Sprague-Dawley rats. Forty healthy weaned Sprague-Dawley rats were randomly equally divided into LPS and control groups. Each rat in the LPS group was injected via the caudal vein with LPS (100 μg/kg b.w.) for 10 days, and the control group was treated with an equal volume of normal saline. On the 1ˢᵗ, 4ᵗʰ, 7ᵗʰ, and 10ᵗʰ days, growth performance, lymphoid organ indexes, and blood cells were evaluated in five necropsied rats. When rats were treated 3–10 times with LPS, their body weight and average daily gains increased more slowly than in the control group (P < 0.05). Repeated LPS treatment significantly increased spleen weight and the ratio of spleen to body weight (P < 0.05). White blood cells, neutrophils, and neutrophil percentage increased (P < 0.05) remarkably, but lymphocyte percentage, haemoglobin, and blood platelet counts decreased significantly (P < 0.05). LPS treatment obviously suppresses growth and promotes peripheral immune organ proliferation. It is indicated that host protective mechanism can be activated by multiple small doses of LPS and prevents organs from further damage during stress status.
Show more [+] Less [-]Anti-fertility effect of hydro-alcoholic extract of fennel (Foeniculum vulgare Mill) seed in male Wistar rats
2016
Introduction: The study aimed to investigate the anti-fertility effect of fennel (Foeniculim vulgare Mill) seed extract in male rats.Material and Methods: Forty Wistar rats were divided into five equal groups. The control group received distilled water and the experimental groups were orally administered 1 ml of hydro-alcoholic extract of fennel seed in four doses of 35, 70, 140, and 280 mg/kg/b.w. daily for 60 days. After the last gavage, the rats were anaesthetised and the caudal part of the right epididymis was used for sperm counting. After fixation of the testes, microscopic sections were prepared and histological changes were evaluated.Results: The number of spermatogonia after doses of 140 and 280 mg/kg and Sertoli cells after a dose of 140 mg/kg decreased significantly as compared with the control group (P < 0.05). The number of primary spermatocytes and sperm count decreased significantly in the experimental groups (70, 140, and 280 mg/kg) when compared to the control group (P < 0.05). Furthermore, thickening of the basement membrane, cell apoptosis, and irregular arrangement of the germinal epithelium were observed in the experimental groups.Conclusion: Hydro-alcoholic fennel seed extract at these doses could reduce reproductivity and has anti-fertility activity in male rats.
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