Keratoconus experimentally produced in mice using collagenase

Introduction: Keratoconus is a relatively common disease of cornea in which structural changes within the cornea cause it to thin and change to a conical shape and scar at the central portion of cornea. So far, few methods and drug treatments were introduced due to both lack of accepted animal models to induce experimental keratoconus and limitation of research in human considering ethical issues. In the present study, keratoconus were produced experimentally in mice focusing on collagen regarding histopathological mechanisms. Methods: In this study, collagenase (1, 3 and 6 mg/ml) were injected into the cornea of male mice. Both macroscopic and microscopic evaluations were performed in short periods of one, three and five days after injection. In macroscopic observations, eyes were graded according to the intensity of keratoconus. Microscopic observations consisted of cornea layers evaluations, presence of inflammation, changes of the cornea thickness, epithelium thickness and collagen and stroma changes. Results: Most cornea damage and changes to more conical shape were observed by 6 mg/ml of collagenase. In fact, collagenase at 3 and 6 mg/ml caused deformity and opacity of cornea, dose dependently in a manner that severe damage to collagen fiber, thinness of cornea and epithelium and cornea rupture, in some cases, were observed at high dose of collagenase.