Investigation of cytotoxic, genotoxic and apoptotic effects of tissue plasminogen activators on retina pigment epithelial cells

Objective: The aim of this study is to investigate cytotoxic, genotoxic, and apoptotic effects of different concentrations of recombinant tissue plasminogen activators (rtPA) on human retina pigment epithelial (RPE) cells. Materials and Methods: In this study, the cytotoxic effect of alteplase and tenecteplase on human RPE cells was measured by luminometric ATP test, the genotoxic effect was measured by alkaline single-cell electrophoresis (Comet Assay) method, and apoptotic effect by acridine orange/ethidium bromide method. In addition, mitochondrial membrane potential (MMP), intracellular calcium (Ca 2+ ), and reactive oxygen species (ROS) levels were measured by different fluorometric methods, and glutathione (GSH) levels were determined by the luminometric method. Also, inflammation markers were examined. Results: Alteplase and tenecteplase reduced statistically significantly GSH and MMP levels while increased cytotoxicity, DNA damage, apoptosis, intracellular Ca 2+ , and ROS levels in RPE cells dose-dependent manner. In addition, we found that alteplase at high concentrations had more cytotoxic, genotoxic, and apoptotic effects than that of tenecteplase. Conclusion: The findings showed that both alteplase and tenecteplase have a dosedependent cytotoxic, genotoxic and apoptotic effec on RPE cells. This study sheds light on the existing literature in the sense that it presents concomitantly the MMP decrease and Ca2+ increase of the alteplase and tenecteplase molecules which induces the apoptotic pathway in the RPE cells and the increase of the intracellular ROS level and the decrease of GSH level inducing cytotoxicity and DNA damage. Moreover, this study shows that alteplase applied at high concentrations have more cytotoxic, genotoxic and apoptotic effects than the tenecteplase. These findings point to the potential reliability of the tenecteplase, one of the rt-PA molecules, in clinical use.