Experimental Therapy Of Bovine Colostrum Against Rotaviruses In Vivo

Background and Object: Rotavirus, a member of the Reoviridae family, is a spherical particle with icosahedral pattern containing double-stranded RNA(ds RNA) virus. Rotaviruses have been classified into seven species(A—G) based on antigenic epitopes on the internal structural protein VP6. Group A rotaviruses cause the portion of diarrheal illness in infants and children. Group B and C rotaviruses have been implicated in gastroenteritis in adults. Group D—G viruses mainly are involved in animal infections. Group A rotaviruses are the most frequent human pathogen. In infants and children, severe loss of electrolytes and fluids may be fatal unless treated. Treatment of gastroenteritis is supportive to correct the loss of water and electrolytes. Bovine colostrum is the initial milk produced by a dairy cow after the birth of the calf. Bovine colostrum contains high concentrations of biological agents that promote protein synthesis and cellular growth in various tissues. Therefore, the aim of this study was to explore the antiviral effects of bovine colostrum on Rotaviruses both in vitro.Methods: A mouse model of gastroenteritis caused by Group A rotaviruses was developed. After infection with viruses, the mice were then given bovine colostrum or Ribavirin via oral route for 1 week. The efficacy of bovine colostrum or Ribavirin was evaluated by recording the mice state of health including loss of body weight and diarrhea and determining the number of viral particles and viral antigens in feces. We measured the levels of IL-6, IL-10, IL-12, TNF, IFN-γ and MCP-1 in the serum of the mice after the inoculation of viruses on days 3 and 7. Finally, we examined the morphological alterations in both the mucous membrane of small intestine and the length of villi of jejunum of bovine colostrum or Ribavirin-treated mice by means of HE stain.Results and Conclusion: The weight of animals was significantly increased in bovine colostrum-treated mice or combined treatment with colostrum and ribavirin-treated mice compared with in control mice. We also found that high dose of bovine colostrum and combined use of colostrum and ribavirin might relieve diarrhea. The viral titer in feces was lower in combined treatment with colostrum and ribavirin-treated mice than in control mice. During acute phase of infection, the levels of IL-6, IL-10 and IFN-γ in serum of colostrum-treated mice or of combined treatment with colostrum and ribavirin-treated mice were significantly lower than those in mice infected with Group A rotaviruses only. In the recovery period after the virus infection, IL-6, IL-10 and IFN-γ returned to the normal levels in both colostrum-treated mice and combined treatment with colostrum and ribavirin-treated mice. Real-time PCR indicated the inhibition of rival replication in intestinal tissue of mice treated with bovine colostrum during acute infection convalescence. Furthermore, we had found the reduced expression of viral antigens and improvement of pathological injury in small intestine of animals treated with bovine colostrum.