The Expression Of Matrix Metalloproteinases And Tissue Inhibitors Of Metalloproteinases In Epiretinal Membrane And Vitreous Of PDR, PVR And ARN Patients

Purpose: To examine epiretinal membranes and vitreous of proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR) and acute retinal necrosis for the presence of matrix metalloproteinases (MMPs) and their natural inhibitors (TIMPs). .Methods: Samples were collected in pars plana vitrectomy. The presence of selected MMPs and TIMPs was investigated in 8 epiretinal membranes of PVR, 9 epiretinal membranes of PDR, 4 epiretinal membranes of ARN and 3 normal retinas by immunohistology. Then MMP-9 was selected for further research. Concentrations of MMP-9 were detected in 13 vitreous samples with PVR, 11 vitreous samples with PDR, 4 vitreous samples with ARN and 6 vitreous samples with nonprolifer retinal detachment by ELISA.Result: The results showed that MMP-1, MMP-3 and TIMP-1,TIMP-2 constitutively express in all eptiretinal membranes and normal retinas. There is no MMP-7 and MMP-9 observed in normal retinas. MMP-1, MMP-2, MMP-3, MMP-7, TIMP-1 and TIMP-2 were stained in membranes of PVR, but only 2 of 8 membranes stained for MMP-9. A characteristic positive staining for all the MMPs and TIMP was observed within the PDR and ARN membranes, and there was a significant increase in MMP-9 expression level in ARN membranes when compared with PVR and PDR membranes. ELISA show that the level of MMP-9 in vitreous samples from PVR, PDR ,ARN were significant higher than that of nonproliferative retinal detachment. But there is no obvious difference between PVR and PDR. Concentration of MMP-9 in ARN was statistically higher than that of PVR and PDR.Conclusion: MMP-1,MMP-3,TIMP-1,TIMP-2 express in normal retinas. MMPs and TIMP involved in degradation of fibrovascular tissue matrix in PVR, PDR and ARN membranes, suggest the existence of common pathways of extracellular matrix degradation in pathological processes leading to retinal neovascularisation and fibrosis. The results indicated that MMPs and TIMP, especially MMP-9, may be involved in vitreoretinopathy, such as PVR, PDR and ARN, but the mechanism is unclear and need further study.