Studies Of Inhibitory Effect Of Bovine Lactoferrin On Hepatitis B Virus By Infecting HepG2 Cell In Vitro

Objective: Lactoferrin which has multi-physiological functions is a natural active glycoprotein.Studies confirm that Lactoferrin can inhibit many viruses, such as human immunodeficiencyvirus(HIV), cytomegalovirus, herpes virusâ… andâ…¡types, Hepatitis C virus(HCV) et al. This paperaimed at studying the inhibitory effect of bovine lactoferrin(BLF), zinc-saturated lactoferrin,iron-saturated lactoferrin and lactoferrin hydrolysate on HBV.Methods: Nature hepatitis B virus (HBV) was used to infect HepG2 cell as model, MTT testwas used to examine cytotoxic effect of BLF, zinc-saturated lactoferrin, iron-saturated lactoferrinand lactoferrin hydrolysate, the maximum nontoxic dose(TD₀) of those agents were determined.TD₀ was used for experiments by diluting in multiple proportion. HBsAg in the culture supernatantwas measured by ELISA. Fluorescence quantify-polymerase chain reaction was used to detectHBV-DNA.Results:(1)Inoculation concentration of 5×10⁴·个·ml^-1 was determined by HepG2 cells culture. 3%serum concentration was used for cell maintenance by growth curve measure.(2)TD₀ of BLF, zinc-saturated lactoferrin, iron-saturated lactoferrin and lactoferrin hydrolysatewere respective 3.0 g·L^-1, 1.5 g·L^-1, 3.0 g·L^-1, 1.5 g·L^-1, and 50% toxic dose(TD₅₀) of BLF was11.08 g·L^-1. Non- cytotoxicity dose of those agents were used in this experiments.(3)After HepG2 cell was infected, HBsAg also could be inhibited by BLF, zinc-saturatedlactoferrin and iron-saturated lactoferrin with dose-dependent relationship, inhibition capabilityorder(inhibition ratio) was zinc-saturated lactoferrin(60.49%)＞BLF(58.34%)＞iron-saturatedlactoferrin (36.66%). But lactoferrin hydrolysate didn't have this function. BLF was shown toinhibit HBV infection into HepG2 cell by protecting corresponding cell sites rather than binding toHBV.(4)After HepG2 cell was infected, HBV-DNA also could be significant inhibited by BLF,zinc-saturated lactoferrin and iron-saturated lactoferrin, but only weekly inhibited by lactoferrinhydrolysate.Conclusion: The result showed that BLF, zinc-saturated lactoferrin and iron,saturatedlactoferrin could significantly inhibit HBV-DNA in HepG2 cells, but lactoferrin hydrolysate couldnot. So the inhibition effect might correlate with integrity and distinct structure of BLF. Its mechanism which is involved in multiple pathways still needs to be dicussed further.