Porcine epidemic diarrhea virus (PEDV) is an enteropathogenic coronavirus; it causes diarrhea in pigs and is associated with high morbidity and mortality in sucking piglets. In this study, we performed in vitro and in vivo experiments to determine the inhibitory effects of Lactobacillus plantarum metabolites (LPM) on PEDV replication. Gas chromatography–mass spectrometry revealed exopolysaccharides to be one of the main components of LPM. We then determine whether L. plantarum exopolysaccharides (LPE) have an antiviral effect and also detected the expression levels of the apoptosis-related genes Bax and Bcl-2 and of the pro-apoptotic protein caspase-3. Further, we assessed the transcription levels of an immune-related protein (STAT1) and antiviral factors (MX1, MX2, ISG15, ZAP, PKR, and OAS1). Our results showed that the most effective method was to pretreat cells with LPM and that the optimal dose of LPM that could be safely administered to Vero cells was 1/8 times of the stock solution. LPE had a strong inhibitory effect on PEDV; the most effective method of administration was to co-incubate cells with LPE and PEDV, and the optimal concentration of LPE was 1.35 mg/mL. To conclude, LPE prevented PEDV adsorption and also alleviated inflammatory responses and induced early apoptosis of injured cells, but it could not regulate the immune function of cells.

猪流行性腹泻病毒（PEDV）是一种肠道致病性冠状病毒；它会导致猪腹泻，并与哺乳仔猪的高发病率和死亡率有关。在这项研究中，我们进行了体外和体内实验，以确定植物乳杆菌代谢物 (LPM) 对 PEDV 复制的抑制作用。气相色谱-质谱法显示胞外多糖是 LPM 的主要成分之一。然后我们确定植物乳杆菌是否胞外多糖 (LPE) 具有抗病毒作用，还检测了凋亡相关基因 Bax 和 Bcl-2 以及促凋亡蛋白 caspase-3 的表达水平。此外，我们评估了免疫相关蛋白 (STAT1) 和抗病毒因子 (MX1、MX2、ISG15、ZAP、PKR 和 OAS1) 的转录水平。我们的结果表明，最有效的方法是用 LPM 预处理细胞，并且可以安全地给予 Vero 细胞的 LPM 的最佳剂量是原液的 1/8 倍。LPE对PEDV有很强的抑制作用；最有效的给药方法是将细胞与 LPE 和 PEDV 共孵育，LPE 的最佳浓度为 1.35 mg/mL。总而言之，LPE 阻止了 PEDV 的吸附，还减轻了炎症反应并诱导了受损细胞的早期凋亡，