Abstract
Abstract: :
Purpose: Connective Tissue Growth Factor (CTGF) is a secretory peptide encoded by an early inducible gene that regulates extracellular matrix production in various cell types. To explore a possible role for CTGF in the modulation of aqueous humor outflow facility, we evaluated CTGF gene expression in trabecular meshwork (TM) cells subjected to various conditions of stress. Methods: Contralateral paired enucleated porcine eyes were perfused at 15 mmHg (control) and 50 mmHg (high pressure) for 5 hours at room temperature. TM was harvested and the expression of CTGF was analyzed by both Western blot analysis and RT–PCR. To analyze the effect of mechanical stress on the regulation of CTGF, porcine TM cells were grown on a collagen coated plastic surface and stretched for 15 hours in a cyclic mode (1 cycle/second) to obtain a 15% final stretch from the baseline condition. Cells were processed for both Western blot and RT–PCR analysis. Results: Perfusion of porcine eyes under high pressure (50 mmHg) for 5 hours resulted in increases in the levels of CTGF protein (50%) in trabecular meshwork tissue as evidenced by Western Blot analysis. This effect was associated with a robust increase in CTGF gene expression (300%) as determined by semi–quantitative RT–PCR. Exposure of porcine trabecular meshwork cells in vitro to mechanical stretch also induced an increase in CTGF protein levels by 10% and gene expression by 36%. Conclusions: This study demonstrates that the expression of CTGF in trabecular meshwork tissue can be influenced by both increased ocular pressure and mechanical stretch. These results suggest that the regulation of CTGF expression potentially may play an important role in the homeostatic response to increased intraocular pressure, possibly by induced alteration of extracellular matrix production in the aqueous humor outflow pathway.
Keywords: trabecular meshwork • extracellular matrix • outflow: trabecular meshwork