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We evaluated the overall genetic damage induced by different doses of cocaine and MDMA (3,4-Methylenedioxymethamphetamine) in several organs. One hour after intraperitoneal drug administration, mice were euthanized; peripheral blood, liver and brain were collected, and the cellular suspensions were used for the single cell gel (comet) assay. We determined that all doses of cocaine and MDMA tested were able to induce DNA damage in blood cells. Extensive genotoxic damage was induced by cocaine or MDMA at the highest doses used in liver cells. Brain cells were affected by all doses administrated. These findings demonstrate that cocaine and MDMA are potent genotoxins.

The aim of this investigation was to evaluate genetic damage induced in male rats by experimental sleep loss for short-term (24 and 96 h) and long-term (21 days) intervals, as well as their respective recovery periods in peripheral blood, brain, liver and heart tissue by the single cell gel (comet) assay. Rats were paradoxically deprived of sleep (PSD) by the platform technique for 24 or 96 h, or chronically sleep-restricted (SR) for 21 days. We also sought to verify the time course of their recovery after 24 h of rebound sleep. The results showed DNA damage in blood cells of rats submitted to PSD for 96 h. Brain tissue showed extensive genotoxic damage in PSD rats (both 24 and 96 h), though the effect was more pronounced in the 96 h group. Rats allowed to recover from the PSD-96 h and SR-21 days treatments showed DNA damage as compared to negative controls. Liver and heart did not display any genotoxicity activity. Corticosterone concentrations were increased after PSD (24 and 96 h) relative to control rats, whereas these levels were unaffected in the SR group. Collectively, these findings reveal that sleep loss was able to induce genetic damage in blood and brain cells, especially following acute exposure. Since DNA damage is an important step in events leading to genomic instability, this study represents a relevant contribution to the understanding of the potential health risks associated with sleep deprivation.