Xylazine and its speedball combination: induction of apoptosis by intrinsic and extrinsic pathway in human umbilical vein endothelial cells

Emerging drugs of abuse, such as xylazine (XYL), are receiving great interest due to increasing use and the potential health toxicity effects, in the addict population. XYL is an alpha two agonist without medical applications in humans. Our previous studies indicated XYL and its combination with cocaine (COC) and/or 6-monoacetylmorphine (6-MAM) induced apoptotic cell death and DNA fragmentation in endothelial cells. In addition XYL and 6-MAM trigger reactive oxygen species (ROS) production in these cells. This study aim is identify apoptosis path way in cell death and determine cell cycle effects of xylazine and its combination with COC and 6-MAM in Human umbilical vein endothelial cells (HUVEC, EA.hy926). HUVEC were treated with XYL (60 μM), COC (160 μM), 6-MAM (160 μM), camptothecin (Positive control, 50 μM), XYL/COC (50 μM), XYL/6-MAM (50 μM) and XYL/COC/6-MAM (40 μM) for a period of 24 hours. Activation of caspases 8 and 9, and cell cycle assessment were analyzed using differential microscopy assays. RESULTS reveal that all drugs tested in this study and their combinations activate caspases 8 and 9, involved in extrinsic and intrinsic pathways respectively. Also, these drugs in combination have presented cell cycle arrest in G2/M phase. While cells treated with COC and 6-MAM, show cell cycle arrest in G0/ G1 phase. The ndings suggest that these drugs trigger apoptotic process in human endothelial cells involving both extrinsic and intrinsic pathways, and furthermore induce cell cycle arrest in two of the major checkpoints. Language: en