RESUMO
OBJECTIVE: To investigate the expression of hepatic Toll-like receptor 1 (TLR1), TLR2 and TLR6 on mice with Schistosoma japonicum infection. METHODS: Fifty BALB/c mice were infected with 20 +/- 3 S. japonicum cercariae through abdominal skin. At 6 weeks post-infection, the mice (n = 10) in treatment group were administered intragastrically with praziquantel [250 microg/(g x d)] for 3 d. The livers of mice (n = 10) were collected at pre-infection and 5, 6, 8 and 12 weeks post-infection, and then the mRNA expression levels of hepatic TLR1, TLR2, TLR6 gene were detected with reverse transfer PCR. Hepatic TLR2, TLR6 protein levels were detected by immunohistochemical staining. RESULTS: The mRNA levels of TLR1, TLR2, and TLR6 on 5, 6, 8 and 12 weeks post infection were significantly higher than that of uninfected mice. After praziquantel treatment, the mRNA level of TLR2 and TLR6 in murine liver of treatment group was lower than that of infection group, but the level of TLR1 mRNA had no obvious change. Furthermore, immunohistochemistry results revealed that the expression of TLR2 and TLR6 proteins in murine liver was up-regulated at 5, 6, 8 and 12 weeks post-infection. After praziquantel treatment, the percentage of TLR2 positive area in liver of infected mice without and with praziquantel treatment were (44.2 +/- 4.3)%, (8.8 +/- 3.1)%, respectively, and TLR2 protein level was considerably down-regulated (P < 0.01). The percentage of TLR6 positive area in liver of infected mice without and with praziquantel treatment was (48.4 +/- 5.4)%, (37.4 +/- 3.5)%, respectively, and TLR6 level decreased slightly (P < 0.05). CONCLUSION: The expression level of TRL2 and TLR6 in murine liver increases after Schistosoma japonicum infection. While compared with TLR2, the role of TLR6 in this progress is a weaker one.
