Expression Of IL-8 And MCP-1 In Human Retinal Pigment Epithelial Cells After Mechanical Injury

Proliferative vitreoretinopathy (PVR) is a serious complication of rhegmatogenous retinal detatchment (RRD) and the most common cause of failure of surgery for rhegmatogenous retinal detatchment. In nature, PVR is a pathological and excessive repair progress and a programmed progress characteristic of period which can be divided into three periods: inflammation, proliferation and scarring stage. Blood-retinal barrier has been destroyed after RD, so blood plasma and inflammation cells can enter the subretinal cavity and vitreous cavity and take part in the inflammation progress after RD.IL-8 and MCP-1 are both important inflammatory factors which were detected at high level in the vitreous of patients with PVR. RPE cells can secrete and express IL-8 and MCP-1 when they are activated by some cytokines and RPE cellsexist in proliferative periretinal membranes.The vitreous pulls retinal neurosensory layer which leads to destruct of the tight junctions between retinal neurosensory layer and retinal pigment epithelium when RD occurs. Mechanical tensile force arrives at retinal pigment epithelium via retinal neurosensory layer and has an effect on the functions of pigment epithelial cells.Mechanical tension can change structure of cellular skeleton and extracellular matrix and accordingly affect cellular proliferation migration and other biological behaviors. Mechanical tension may act on cellular internal through extracelluar matrix, thereby alter cellular biological behaviors. Changed shape of extracelluar matrix can also influence cellular skeleton, consequently influence cellular biological behaviors.The starting point of PVR should be injury of RPE cells, but reaction mechanism of RPE cells to injury is still unknown. It is well known that IL-8 and MCP-1 exist in the eyes of patients with PVR and play a role in the progress of PVR. RPE cells can synthesize and secrete IL-8 and MCP-1 under certain circumstances such as with help of IL-1 and TNF- . Alveolar epithelium intestinal epithelium and bronchial epithelium can produce IL-8 and MCP-1 after they fall off because of mechanical tension. In order to understand further pathogenesis of PVR and proliferation and control of RPE, we studied synthesis and expression of IL-8 and MCP-1 both inproliferative periretinal membranes and by cultured RPE cells after injury.Part one Expression of IL-8 and MCP-1 in human proliferative periretinal membranes. Objective The aim of this section was to investigate the expression of IL-8 and MCP-1 in human proliferative periretinal membranes. Method Twenty-four specimens of periretinal membranes of PVR (11 of C grade and 13 of D grade) obtained during vitrectomy were studied by immunohistochemical staining to determine the expression of MCP-1 and IL-8. Results Immunohistochemical study indicated that MCP-1 and IL-8 had both a positive staining in all the periretinal membranes of PVR. MCP-1 had a positive staining in 8 of 24 membranes and a strong positive staining in the remaining; IL-8 had a positive staining in 7 of 24 membranes and a strong positive staining in the rest. Among the 11 grade C periretinal membranes, 5 displayed a positive staining for MCP-1 and 4 for IL-8; 6 displayed a strong positive staining for MCP-1 and 7 for IL-8. Among the 13 grade D periretinal membranes, the corresponding numbers were 3, 3, 10 and 10 respectively. The control specimens showed negative staining. Conclusion IL-8 and MCP-1 both exist in periretinal membranes which indicates that they may play an important role in the formation progress of periretinal membranes and development of PVR.Part two Expression of IL-8 and MCP-1 in human retinal pigment epithelial cells after mechanical injury. ObjectiveTo study synthesis and expression of IL-8 and MCP-1 by cultured RPE cells after injury. Method When RPE cells were in the state of confluence in 6 well plate, we wiped off the same area of RPE cells per well. Supernatant was collected after 72h and used to examine expression of IL-8 and MCP-1 by ELISA. At the same time we d...