Expression Of Adhesion Molecule CD44v6 In Three Kinds Of Hyperplastic Epiretinal Membrane

[Objective]Proliferative vitreoretinopathy(PVR), as one of the most severe complications of diabetic retinopathy and eye trauma, is a major cause of failure in rhegmatogenous retinal detachment. A variety of cellular components, such as retinal pigment epithelium (RPE) , glial cell, fibroblast and macrophage are involved in the formation of PVR with hyperplasia, adhering to epiretina and inferior of the retina to form epiretinal membrane(ERM). The contraction of ERM is inclined to resultin tractional detachment of retina, even atrophia bulbi. Therefore PVR is regarded as one of the main causes of blindness. Since expectation cannot be satisfied by surgery, to find a drug therapy to prevent the development of PVR has become the new hot spot in the field of eye research. It mainly depend on the deep understand of etiology of PVR.Cell adhesion molecule is a major theme in normal biological processes and pathological disturbances involving cell-cell and cell-matrix interactions. The process is controlled by the expression and function of adhesion receptors and by encounter with the corresponding ligands. It is crucial in the process of embryonic development, inflammation, immune response, thrombosis and tumor metastasis. It is reported that adhesion molecule CD44v6 has been found in the ERM of PVR in patients with rhegmatogenous retinal detachment. However no report refers it to diabetic retinopathy and eye trauma. The purpose of this study is trying to detect CD44v6 in three different kinds of ERM, rhegmatogenous retinal detachment, diabetic retinopathy and eye trauma, by method of immunohistochemistry, and to compare with each other, and to analyze the function of CD44v6 in the formation of ERM, in order to offer feasible therapy for the prevention of PVR.[Methods]46 ERM samples were collected, within which 19 samples werefrom patients with rhegmatogenous retinal detachment (Group A), 15 samples from diabetic retinopathy (Group B), and 12 samples from eye trauma (Group C). All the samples were dyed with HE stain after paraffin section in order to observe the pathologic changes. Furthermore intact ERMs were stained by method of immunohistochemistry, and Supervision? system (agent A: CD44v6 mAb, agent B: Supervision? Anti-Mouse-HRP detect system) was used to detect the expression of CD44v6 in each group. Expression rate (ER) was analyzed and compared with each other.[Results]Light microscope: In the ERMs from patients with course less than 6 months, cell constitutes the major part, but little interstitium and collagen fibers, while cell component decreased, interstitium and collagen fibers increased in the ERMs from those with course more than 6 months. RPE, fibroblast-like cell and macrophage-like cell appear in all the ERMs, though the proportion is different. Interestingly, there is much more new vessels in group B.Observations of immunohistochemical stain: Generally, CD44v6 was expressed in 27 of the 46 samples with total ER 58.7%, 13 in group A (68.4%), 11 in group B (73.3%) and 3 in group C (25.0%). ER is similar between group A and group B (P=1.000) , but ER is lower ingroup C than that in group A (P=0.029) and that in group B (P=0.021). Besides, in group A, CD44v6 was expressed in 7 samples in the 11 ERMs of PVR-C with ER 63.6%, while it was expressed in 6/8 ERMs of PVR-D with ER 75.0%. No difference was detected between group PVR-C and group PVR-D (P=L000).[Conclusion]1. Adhesion molecule CD44v6 is not only expressed in ERM from rhegmatogenous PVR, but also in ERM from diabetic retinopathy and eye trauma with different ER.2. The CD44v6 ER similarity between group A and group B indicates the similar function CD44v6 plays in the development of rhegmatogenous PVR and proliferative diabetic retinopathy.3. The difference between group C and group A, B indicates that traumatic PVR may develop in an otherwise mechanism.4. Adhesion molecule plays a part in the development of PVR.