[Expressions and significance of TLR2 and TLR4 in Kupffer cells of tree shrews chronically infected with hepatitis B virus].

OBJECTIVE:To investigate the mRNA expression levels of Toll-like receptors 2 (TLR2) and TLR4 in Kupffer cells of tree shrews that were chronically infected with hepatitis B virus (HBV), and the effects of these receptors on the function of Kupffer cells. METHODS:The tree shrews were divided into tree shrews proved with chronic HBV infection, tree shrews suspected with chronic HBV infection, and normal control tree shrews without hepatitis B vaccination. The samples of serum and liver biopsy were collected periodically, and the levels of HBV DNA in serum and liver tissues were detected by fluorescence-based quantitative real-time PCR (qRT-PCR). Meanwhile, Kupffer cells were isolated from the biopsied liver tissues, and then purified and primarily cultured. Afterwards, qRT-PCR was applied to detect the mRNA expression levels of TLR2, TLR4 and TNF-α in the Kupffer cells. Cell migration assay and lysosome-specific fluorescent probe were adopted to analyze the effects of TLR2 and TLR4 on the migration capacity of Kupffer cells and the quantity of lysosomes in these cells. RESULTS:The mRNA expression levels of TLR2 and TLR4 in tree shrews proved with chronic HBV infection were lower than those in the ones suspected with chronic HBV infection and normal controls without hepatitis B vaccination (P<0.05), and these expression levels were all negatively correlated with the level of HBV DNA in liver tissues of the animals (P<0.05), but were positively correlated with the number of migrated Kupffer cells, the density of lysosomes and the mRNA expression level of TNF-α (P<0.05). CONCLUSION:TLR2 and TLR4 in Kupffer cells may play important roles in the chronic process of hepatic pathological changes in tree shrews infected with HBV through their influence on the function of Kupffer cells.