CYCLOSPORINE-A-INDUCED GINGIVAL OVERGROWTH IN ROTS - MACROSCOPIC AND MICROSCOPIC OBSERVATIONS

Because the existence of cyclosporin A-induced gingival overgrowth in animals has not been well established a pilot study was undertaken to determine whether such gingival overgrowth could be observed in Spragu e-Dawley rats. Thirty-six male rats, age 6 weeks, were randomly divide d into two groups. The test group was given 30 mg/kg of body weight of cyclosporin A daily by gastric feeding. The control group was given m ineral oil instead. Stone casts of the gingiva in the mandibular incis or region were made biweekly for 6 weeks. The three-dimensional growth pattern-the buccolingual width, the mesiodistal width, and the vertic al height of the gingiva-was analyzed on the casts, The animals were k illed after the last impression was taken, and tissue sections were ma de. Stereomicroscopy revealed marked overgrowth of the gingiva in the test rats. All three-dimensional measurements on the stone casts were greater in the test group, beginning 2 weeks after cyclosporin A was g iven. Histologically the overgrowth of the epithelia and connective ti ssue was easily confirmed in the buccal and lingual gingiva of the tes t rats.