Effects Of Qiwei Baizhu Powder On The Expression Of IFN-γ And IFN-γ Receptor In Small Intestinal Mucosa Of HRV Infection Suckling Mice

Aim of this study:The study was aimed to investigate the protection mechanism of Qiwei Baizhu Powder (QWBZP) on small intestinal mucosa of HRV infection Suckling Mice.Materials and methods:1. HRV titer was determined by cytopathic effect (CPE) in MA-104 cells and was expressed as 50% tissue culture infective dose (TCID50) per 0.1ml. 2. Enzyme-linked immunosorbent assay (ELISA) was taken to determine the levels of HRV antigen in the feces of suckling mice which was collected 24h after HRV inoculation. The highest dilution that caused diarrhea in 100% of suckling mice was defined as inoculation dose.3.5-day-old suckling mice were orally inoculated with inoculation dose HRV and were randomly assigned to 6 groups:Control group (NG), Model group (MG), QWBZP group (BG), Ribavirin group (ZG), Genistein group (YG) and Combined group (BYG). QWBZP, Ribavirin, Genistein and physiological saline were administered by oral gavage three times a day respectively after the detection of HRV antigen in the feces of suckling mice.4. Pups were sacrificed and their small intestines were removed at specified time respectively (15min,2h, 6h,12h,24h,32h,48h and 5 days after treatment). The histological assessment of the lesions in intestine was determined after hematoxylin and eosin staining (HE staining); The distribution and expression level of IFN-γR in intestine mucosa were detected by immunohistochemical method and the expression levels of IFN-γand IFN-γRmRNA were detected by RT-PCR.Results:1. Pathological changes in intestine QWBZP reduced the impairment of HRV to small intestine tissues evidently after treated for 5 days. There were statistically significant differences present in ZG, YG and BYG compared with NG (P<0.05).2. Expression level of IFN-γmRNA①There were statistically significant differences present between NG and MG (P<0.05). IFN-γmRNA levels in BG (2h,6h,12h,24h,32h,48h) increased obviously and had statistical significance compared with MG (P<0.05). IFN-γmRNA levels kept at higher level until 24h later. This supposed that QWBZP can improve the expression of IFN-γmRNA after treated for 2h and had two-ways regulation on IFN-γmRNA expression.②IFN-γmRNA levels in ZG (2h,6h,12h,24h,32h) had statistical significance compared with MG (P<0.05); IFN-γmRNA levels in BG (6h, 12h,24h,32h,48h) had statistical significance compared with ZG (P<0.05), which suggested that the promotion of QWBZP on IFN-γmRNA expression was stronger than Ribavirin.③IFN-γmRNA levels in YG(2h,6h,12h,24h,32h,48h) were lower than that in MG and had statistical significance compared with MG (P<0.05). IFN-γmRNA levels in BYG (2h,12h,24h,32h,48h) had statistical significance compared with YG (P<0.05). These revealed the inhibition of Genistein IFN-γmRNA expression and the antagonistic inhibition of QWBZP on Genistein.3. Expression level of IFN-γRmRNA and optical density value of IFN-γR①The results of correlation analysis between the levels of IFN-γR and IFN-γmRNA in corresponding groups shown positive linear correlation.②Optical density values of IFN-γR which were determined by immunohistochemical method were matched with the results detected by RT-PCR.Conclusion: QWBZP can reduce the impairment of HRV to small intestine tissues evidently and up-regulate the expression levels of IFN-γand IFN-γR in small intestinal mucosa of HRV infection suckling mice, which suggests the regulation effect of QWBZP on IFN-γand IFN-γR in small intestinal mucosa may be one of the mechanisms on treating HRV infectious diarrhea.