·AIM:To observe the inhibition of krypton induced choroidal neovascularization(CNV)of brown norway(BN)rat by intravitreal triamcinolone acetonide(TA)injection after photocoagulation,and to study the mechanism of inhibition of CNV growth.·METHODS:Thirty-six healthy BN rats were divided randomly to two groups,one eye was chosen randomly as experimental eye.After establishing BN rat CNV model,8μL(320μg)TA was injected in vitreous immediately after photocoagulation in treatment group,the same volume isotonic balanced salt solution(BSS)was injected in vitreous in the contrast group.Eyes of 6 BN rats were enucleated for histological slices in 1 week,2,4 weeks.The protein expression of nuclear factor-kappa B(NF-κB),monocyte chemoattractant protein-1(MCP-1),factorⅧ-related antigen(FⅧ-RAg)was examined by immunohisto-chemical method,and the transcription of vascular endothelial growth factor mRNA(VEGFmRNA)was Examined by in situ hybridization,meanwhile semiquantitative analysis was conducted.·RESULTS:In treatment group,the positive stain optical den-sity of NF-κB,MCP-1,FⅧ-RAg,and VEGFmRNA was obvi-ously lower the contemporaneous control group(P<0.05).·CONCLUSION:TA can lower the expression of VEGF mRNA transcription and the protein expression of NF-κB,MCP-1 and FⅧ-RAg,so it can effectively inhibit the develop-ment of BN rat CNV,which indicats that TA is an effective drug to treat CNV.·