The Role Of TlR4 In Transcription Control Of Vascular Endothelial Growth Factor In The Cultured Human Retinal Pigment Epithelial Cells Under Hypoxia

Objective:To observe the differential expression of TLR4 and VEGF in cultured human RPE cells under normoxic and hypoxic condition and ,to explore the influence of hypoxia on the expression of TLR4 and VEGF in LPS pretreated RPE cells.Method:1. Chemical hypoxic model was established by treating the cultured human RPE cells with 1‰COCl2. The location of TLR4 in human RPE cells was observed by immunofluorescence assay and, RT-PCR together with Western blot was applied to detect the expression of TLR4 and VEGF at 0h,2h,4h,8h,12h,24h after treatment.2. 3 hours after LPS pretreatment, the expression of TLR4 and VEGF in hypoxic human RPE cells was detected by RT-PCR and Western blot , at 0h,2h,4h,8h,12h after 1‰COCl2 treatment, as forementioned.Results:1.Immunofluorescence assay revealed that TLR4 was slightly expressed in normoxic human RPE cells. After hypoxic treatment, TLR4 expression tend to intensify over time and peaked at 12h,which was confirmed by RT-PCR and Western blot assay exhibiting TLR4 and VEGF mRNA/protein levels.2.Human RPE cells in LPS pretreated group expressed a higher level TLR4 and VEGF mRNA/protein at each point-in-time() compared with non-pretreated group(p<0.01).Conclusion:1. TLR4 is present in cultured human RPE cells.2. Hypoxia can strengthen TLR4 and VEGF expression in RPE cells.3. LPS can regulate VEGF expression through up-regulation of TLR4.