Effects of acetylcholine and carbachol on bovine corneal endothelial cells in vitro

Abstract

Purpose: To assess the relative cytotoxicity of Miochol® (1% acetylcholine and mannitol), Miostat® (0.01% carbachol, sodium, potassium, magnesium, and calcium salts), and their individual components using in vitro models of bovine corneal endothelial cells (BCECs).Setting: Laboratories of the Departments of Ophthalmology and Physiology, The University of Texas Health Science Center, Houston.Methods: The study was divided into four experiments. Experiment 1 used a confluent model to compare the relative cytotoxicity of Miochol and Miostat on BCECs following short-term exposure. In Experiments 2, 3, and 4, the proliferation model (preconfluent BCECs) was used to detect the possible cytotoxicity of individual components in the commercial preparations of the miotics; i.e., the preconfluent BCECs were exposed to buffered salt solutions containing mannitol (1 %, 3%, and 4%), acetylcholine (0.5%, 1 %, and 2%), or carbachol (0.1 %, 0.5%, and 1 %) for 3 hours.Results: Confluent BCECs exposed to Miochol for 30 minutes underwent necrosis and degeneration, while those treated with Miostat did not show any morphological changes. None of the tested solutions except 2% acetylcholine and 1 % carbachol caused observable changes in the nuclear densities of BCECs at 24, 72, 120, and 168 hours.Conclusion: The major components of Miochol (acetylcholine and mannitol) were found to be nontoxic; the cytotoxicity of the preparation was possibly due to the lack of an appropriate balanced salt solution. These findings may influence the selection of a miotic for use during intraocular surgery.