菊苣酸对仔猪人工感染猪德尔塔冠状病毒的保护效果研究

Study on the protective effect of the cichoric acid to piglet infected with porcine deltacoronavirus

为评价菊苣酸对猪德尔塔冠状病毒(PDCoV)的攻毒保护效果,本研究选取36头8日龄的哺乳仔猪随机分成4组:菊苣酸组、菊苣酸+攻毒组、攻毒组、空白组,每组9头。菊苣酸组和菊苣酸+攻毒组仔猪从实验第1 d开始每天口服菊苣酸(3.6 mg/kg体重)至实验结束;实验第3 d,攻毒组和菊苣酸+攻毒组仔猪再口服10 mL PDCoV NC分离株(10~5TCID/mL)进行攻毒,空白组和菊苣酸组仔猪口服10 mL DMEM,在7 d的观察期内对各组仔猪的平均日增重和腹泻情况统计;实验第7 d,对所有仔猪剖检观察各肠段的剖检病变和病理变化。结果显示:实验期间攻毒组仔猪的腹泻比菊苣酸+攻毒组更严重,且攻毒组仔猪的平均日增重显著低于菊苣酸+攻毒组、空白组和菊苣酸组(P<0.05),而菊苣酸+攻毒组与空白组、菊苣酸组的平均日增重无显著差异。剖检病变及组织病理学检测可见,攻毒组仔猪小肠组织的病变比菊苣酸+攻毒组更严重,可观察到大量的肠绒毛脱落。利用荧光定量PCR方法检测各组仔猪小肠的病毒载量及抗病毒基因的转录水平,结果显示,与攻毒组相比,菊苣酸+攻毒组空肠和回肠中的抗病毒基因OAS、Mx1和PKR的转录水平增加,而PDCoV载量显著下降。以上结果表明,仔猪口服菊苣酸后可减少PDCoV对仔猪肠道的损伤。本研究首次报道了菊苣酸可以为仔猪提供抵抗PDCoV攻击的能力,为菊苣酸抗病毒机理研究和临床防控PDCoV的感染提供了参考依据。

To evaluate the protective effect of cichoric acid against PDCoV,36 8-day-old suckling piglets were randomly divided into 4 groups in this study,with 9 pigs in each group.Each piglet in the cichoric acid group and cichoric acid+challenge group was given orally cichoric acid (3.6mg/kg body weight) every day;on the 3rd day of the experiment,each piglet in the challenge group and the cichoric acid+challenge group was orally administered 10mL of PDCoV NC isolate (10~5TCID/mL) for challenge,while each piglet in the blank group and cichoric acid group was orally administered 10mL DMEM;on the 7th day,all piglets were subjected to necropsy.Statistics analysis was performed for the average daily weight gain and the degree of diarrhea in piglets in each group,and the results showed that during the experiment,the diarrhea degree of the piglets in the challenge group was more serious than that in the cichoric acid+challenge group,and the average daily gain of the piglets in the challenge group was significantly lower than that in the cichoric acid+challenge group,control group and cichoric acid group (P<0.05),while the average daily gains of cichoric acid+challenge group,control group and cichoric acid group have no significant difference.Pathological and histopathological examinations showed that the small intestinal tissue lesions of the piglets in the challenge group were more serious than those in cichoric acid+challenge group,and a large number of intestinal villi were shed.The real time PCR was used to detect the PDCoV load and the amount of antiviral gene in the small intestine of piglets in each group,results showed that compared with the challenge group,the amounts of antiviral genes OAS,Mx1 and PKR in the jejunum and ileum of the cichoric acid+challenge group were increased,while the PDCoV were decreased significantly.The above results indicate that the damage of PDCoV to the intestinal tract caused by PSCoV was reduced for the piglets given orally cichoric acid.This study first reported that cichoric acid has a protective effect on the piglets with PDCoV challenge,providing theoretical basis for the studies of cichoric acid’s antiviral mechanism and clinical prevention and control of PDCoV.