Shao Qi, Huang Junjie, Li Jingui
College of Veterinary Medicine, Yangzhou University, Yangzhou, China.
Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.
Front Vet Sci. 2021 Nov 17;8:759812. doi: 10.3389/fvets.2021.759812. eCollection 2021.
Viral disease management has been proven difficult, and there are no broadly licensed vaccines or therapeutics. Vesicular stomatitis virus (VSV) is an active pathogen of wild ungulates and livestock; its infection frequently caused irreversible vesicles on the tongue or other positions, leading to enormous economic loss. Tea tree oil (TTO) has been shown to be a popular remedy for many skin diseases owing to its antibacterial, antipruritic, and anti-inflammatory effects. However, the potential effect of TTO on VSV proliferation and the corresponding inflammatory response in cells remain unclear. In this study, methyl thiazolyl tetrazolium assay was used to evaluate the cell viability of TTO, and cytotoxic concentration 50 (CC50) was calculated. Then, fluorescence observation, reverse transcription-quantitative polymerase chain reaction, Western blot (WB), and flow cytometry (FCM) assay were used to evaluate the antiviral effect of TTO against VSV under three manners of pre-infection before medication, co-administration, pretreatment before infection at safe doses to Vero cells. Meanwhile, the mRNA expressions of interleukin 8, tumor necrosis factor α, and ISG56 in cells were also detected. The results showed that the maximum safe concentration of TTO to Vero cells was 0.063% and the CC50 is 0.32%. Most notably, TTO dose-dependently inhibited the VSV GFP fluorescence generation and restrained the replication of VSV in gene and protein levels regardless of the treatment modes. Based on the results of the FCM, effective concentration 50 of TTO against VSV is 0.019%. Similarly, the mRNA expression of the above cytokines induced by viral infection was also remarkably curbed. These findings suggest that TTO emerged blocking, prophylaxis, and treatment action against VSV replication and suppressed the related inflammation in Vero cells. This study provides a novel potential for TTO fighting against viral infection and anti-inflammatory activities in Vero cells.
病毒性疾病的管理已被证明具有难度，并且目前尚无广泛获批的疫苗或治疗方法。水泡性口炎病毒（VSV）是野生有蹄类动物和家畜的一种活跃病原体；其感染经常在舌头或其他部位引起不可逆的水泡，导致巨大的经济损失。茶树油（TTO）因其抗菌、止痒和抗炎作用，已被证明是治疗多种皮肤病的常用药物。然而，TTO对VSV增殖的潜在影响以及细胞中的相应炎症反应仍不清楚。在本研究中，采用甲基噻唑基四氮唑法评估TTO的细胞活力，并计算细胞毒性浓度50（CC50）。然后，采用荧光观察、逆转录定量聚合酶链反应、蛋白质免疫印迹（WB）和流式细胞术（FCM）检测，在药物预处理、联合给药、感染前安全剂量预处理三种方式下，评估TTO对Vero细胞VSV的抗病毒作用。同时，还检测了细胞中白细胞介素8、肿瘤坏死因子α和ISG56的mRNA表达。结果表明，TTO对Vero细胞的最大安全浓度为0.063%，CC50为0.32%。最值得注意的是，无论采用何种处理方式，TTO均呈剂量依赖性抑制VSV绿色荧光蛋白荧光的产生，并在基因和蛋白质水平上抑制VSV的复制。基于FCM结果，TTO对VSV的半数有效浓度为0.019%。同样，病毒感染诱导的上述细胞因子的mRNA表达也受到显著抑制。这些发现表明，TTO对VSV复制具有阻断、预防和治疗作用，并抑制了Vero细胞中的相关炎症。本研究为TTO在Vero细胞中对抗病毒感染和抗炎活性提供了新的可能性。
