Abstract
Abstract: :
Purpose: The purpose of this study was to examine patterns of cornea specific cytokeratin expression over the ocular surface, following pre-ganglionic parasympathetic denervation of the eye. Methods: Unilateral preganglionic parasympathetic denervation was carried out by sectioning the greater superficial petroseal nerve (GSPN) in seven (n=7) New Zealand white rabbits. The rabbits were sacrificed at 1 week (n=4) and 2.5 months (n=3) and tissues (cornea, limbus, fornix, bulbar, and tarsal conjunctiva) were frozen in liquid nitrogen. Western blot analysis was carried out using antibodies specific to K3 and K12; cell proliferation was compared using an antibody to PCNA in the control and denervated side. Human corneal epithelium was used as a positive control for K3 and K12. Specific binding was visualized using an ECL-plus detection system, exposed on x-ray film, and density was analyzed using Sigma Gel and Eagle Sight Software (3.2 version). Results: Blots for K3 and K12 were positive for the cornea and limbus in the control eye and for the human corneal epithelium, but neither K3 or K12 were found in the fornix, bulbar or tarsal conjunctiva. Sectioning the GSPN resulted in decreased levels of K3 in the cornea. At 2.5 months, mean density of K3 in the control cornea was significantly higher than the denervated side 52639 + 23660 and 11201 + 4942 (Mean + SEM) (n=3). In the limbus, K3 was not significantly different in the control and denervated sides. K12 (n=3) expression was low in the control tissues and was further decreased in the cornea and limbus in the denervated side. Blots for PCNA (n=4) were positive for the cornea, limbus, fornix, tarsal and bulbar conjunctiva. The level of PCNA expression was higher in control tarsal and fornix conjunctiva than in the denervated side at 1 week, but the levels were not significant. Conclusions: GSPN section resulted in decrease expression of cytokeratin 3 and 12 in the cornea. This suggests that parasympathetic innervation plays an important role in the proliferation and maintenance of corneal differentiation. Supported in grant by EY12416
Keywords: cornea: basic science • protein structure/function • innervation: neural regulation