Studies Of Inhibitory Effects Of Metal Ions And Lactoferrin On Hepatitis B Virus 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 immunodeficiency virus(HIV), cytomegalovirus, herpes virusⅠandⅡtypes, Hepatitis C virus(HCV) et al. This paper aimed at studying the inhibitory effect of apo-lactoferrin(apo-BLF), zinc-saturated lactoferrin, iron-saturated lactoferrin and Manganese-saturated lactoferrin on HBV.Methods: Nature hepatitis B virus (HBV) was used to infect HepG2 cell as model, MTT test was used to examine cytotoxic effect of apo-lactoferrin, zinc-saturated lactoferrin, iron-saturated lactoferrin and Manganese-saturated lactoferrin, the maximum nontoxic dose(TD0) of those agents were determined. TD0 was used for experiments by diluting in multiple proportion. HBsAg in the culture supernatant was measured by ELISA. Fluorescence quantify-polymerase chain reaction was used to detect HBV-DNA. Results:⑴MTT test was used to examine cytotoxic effect of apo-lactoferrin, Zinc-saturated bovine lactoferrin, Iron-saturated bovine lactoferrin and Manganese-saturated bovine lactoferrin. TD0 of apo-lactoferrin, zinc-saturated lactoferrin, iron-saturated lactoferrin and Manganese-saturated bovine lactoferrin were respective 1.5 g?L-1, 1.5 g?L-1, 3.0 g?L-1and 1.5 g?L-1, and 50% of toxic dose(TD50) of apo-BLF was 8.312 g?L-1. Non-cytotoxicity dose of those agents were used in this experiments.⑵After HepG2 cell was infected, HBsAg could not be inhibited by apo-lactoferrin(the highest inhibition ratio was only 14.78%), and apo-lactoferrin had also weekly effect on inhibiting hepatitis B virus DNA(P>0.05), so hepatitis B virus could not be inhibited by apo-lactoferrin.⑶After HepG2 cell was infected, hepatitis B virus DNA also could be significant inhibited by zinc-saturated bovine lactoferrin, iron-saturated bovine lactoferrin and Manganese-saturated bovine lactoferrin with dose-dependent relationship(P<0.05), inhibition capability order was zinc-saturated bovine lactoferrin>Manganese-saturated bovine lactoferrin>iron-saturated bovine lactoferrin. Lactoferrin was shown to inhibit hepatitis B virus DNA by the different kind of ion which sequestration with the bovine lactoferrin.⑷After HepG2 cell was infected, hepatitis B virus DNA also could not be significant inhibited by Zn, Fe and Mn. the result showed that the lactoferrin which has whole constitution can inhibit hepatitis B virus DNA, the inhibition effect was not from Zn, Fe, and Mn. Conclusion: The result showed that zinc-saturated lactoferrin, iron-saturated lactoferrin and manganese-saturated lactoferrin could significantly inhibit hepatitis B virus DNA in HepG2 cells, but apo-lactoferrin, Zinc, Iron and Manganese could not. So the inhibition effect might correlate with integrity and distinct structure of bovine lactoferrin. Its mechanism which is involved in multiple pathways still needs to be dicussed further.