Localization and Developmental Expression Patterns of CSPG in the RCS Rat Retina

PURPOSE: Investigate changes in chondroitin sulfate proteoglycan (CSPG) distribution in Royal College of Surgeons (RCS) rat retinae. Could CSPGs distribution act as a physical barrier to transplanted cell migration in degenerating retinae? METHODS: CSPG expression was examined in RCS and Long-Evans rat retinae from birth to postnatal day 150 (PND150) using immunofluorescence and western-blots. RESULTS: Both groups showed a rapid rise in CSPG expression on PND14, which peaked on PND21 before declining to lower levels by PND35. CSPG expression had risen again by PND90 and remained elevated for the duration of the study (PND150). However, from PND21, CSPG expression was significantly higher (p ≤ 0.05, n = 5) in Long-Evans rat retinae. CSPG-positive cells were localized in the ganglion cell layer (GCL) and the photoreceptor outer segment debris zone (DZ); CSPG expression in the DZ was the main contributor to the higher expression in older animals for both groups. CONCLUSIONS: Increased expression of CSPGs in the DZ may act as a physical barrier following retinal cellular transplantation. CSPGs in the GCL is probably related to dendritic changes. CSPG accumulation in the older retinae suggests that aging influences the microenvironment in the retina, which may affect the efficacy of cell transplantation.