Histopathological and cytological study on inner limiting membrane in idiopathic macular hole

Background Researching the pathological characteristics and components of cells in internal limiting membrane of idiopathic macular hole (IMH) has an important clinical significance for the prevention of IMH.However, the study results are still disputable. Objective This study was to investigate the histopathological features of internal limiting membrane of IMH and the types of cells inside it, and explore the pathomechanism of IMH. Methods Seven specimens of internal limiting membrane were obtained during the vitrectomy with IMH patients in the Second Affiliated Hospital of Guangzhou Medical University from February 2012 to August 2013 under the informed consent of patients.The histopathological examination was performed for the structural observation and cellular identification of internal limiting membrane.The expression and location of glial fibrillary acidic protein (GFAP), CD45 and CD44 in internal limiting membrane were examined by using immunochemistry and immunofluorescence technology. Results All the seven specimens showed continuous undulating membrane with red staining.Two specimens appeared to be uniform in thickness and few cells were distributed in the specimens.The internal limiting membranes were uneven in thickness in the other specimens with retinal pigment epithelial cells, neuroglia cells, fibrocytes, macrophages and lymphocytes in them.Immunochemistry showed the positive expression of GFAP in the outer layer of the specimens.CD45 positive cells were detected in the internal limiting membranes, and CD44 was detected in the inner layer of the specimens. Conclusions Few cells exist in the internal limiting memranes of IMH.However, neuroglia cells and CD45 positive cells emerge in the internal limiting memranes of stage 3 or above IMH eyes, indicating the proliferation of cells and immuno-inflammation response exist during the IMH development.The up-regulation of CD44 expression promotes inflammatory response of internal limiting memranes. Key words: Macula lutea/pathology; Retinal perforations/etiology; Internal limiting membrane/pathology, cytology; Histocytological examination; Immunohistochemistry; Adhesion molecule/pathology; Humans; Idiopathic macular hole