Abstract: Objective　To investigate the expression of Toll like receptor 3,4 (TLR3,4) in oral squamous cell carcinoma (OSCC) cells lines cultured in normoxia, and to further investigate the effect of tumor hypoxia microenvironment on its expression. Methods: OSCC cell line HSC3 was cultured under normoxia conditions. Afterreachingthe exponential growth phase, the cells were collected and Real-time PCR and Western blotting were applied to detect the expression of TLRs at mRNA and protein levels respectively. Tumor hypoxia microenvironment was mimiced by exposing the cells to hypoxia(1%O2) for 0,3,6, 12 and 24h . Both Real-time PCR and Western blotting were applied to detect the expression change of TLR3 and TLR4. Results The expression of TLR3 and TLR4 could be detected in normoxia state. After the stimulation of hypoxia, the expression level improved significantly. Among these, the protein expression of TLR3 could increase to 6.2±0.1 times after the stimulation of hypoxia for 24 hours, while the expression of TLR4 could reach 5.6±0.1 times, which was statistically significant（p＜0.05). Conclusions The expression of TLR3 and TLR4 in HSC3could be detected in normoxia state. Hypoxia could further promote its expression.

Key words: Oral squamous carcinoma cells, Toll like receptor 3,4, Hypoxia