Evaluation of DNA damage in rat lymphocytes exposed to tulathromycin in vitro

Tulathromycin is a relatively new semi-synthetic macrolide antibiotic, a member of the triamilide group, approved primarly for the treatment of respiratory diseases in cattle and swine. Various genotoxicological studies indicated that tulathromycin is not genotoxic, but no available published data originate from the single-cell gel electrophoresis (Comet) assay. Therefore, the objective of this study was to examine whether it can induce primary DNA damage using in vitro Comet assay in isolated rat lymphocytes. Lymphocytes were treated with a broad spectrum of tulathromycin concentrations (from 1 to 100 ? M) and co-treatment with an antioxidant, catalase (100 IU/mL and 500 IU/mL) was performed. The highest concentrations of tulathromycin (50 and 100 ? M) caused significant increase of DNA damage in rat lymphocytes and catalase did not significantly reduce the DNA-damaging effect of tulathromycin. The results of this study indicate that tulathromycin induces genotoxic effects at high concentrations, that catalase does not exert protective effect in this case.

Combined Cytogenotoxic Effects of Bee Venom and Bleomycin on Rat Lymphocytes: AnIn VitroStudy

This study was carried out to determine the cytotoxic and genotoxic effects of bee venom (BV) and/or the chemotherapeutic agent bleomycin (BLM) on healthy isolated rat lymphocytes utilizing morphometric and molecular techniques. Using the Ficoll-Histopaque density gradient centrifugation technique, lymphocytes were isolated, divided into groups, and subjected to BV and/or BLM at incubation medium concentrations of 10 or 20 μg/mL respectively for 24 and 72 hrs. An MTT assay and fluorescent microscopy examinations were used to assess the cytotoxic effects. To determine the predominant type of BV and/or BLM-induced cell death, LDH release assay was employed beside quantitative expression analyses of the apoptosis-related genes (Caspase-3 and Bcl-2). The genotoxic effects of the tested compounds were evaluated via DNA fragmentation assay. The results of these assays demonstrated that BV potentiates BLM-induced cytotoxicity through increased LDH release and diminished cell viability. Nevertheless, BV significantly inhibited the BLM-induced DNA damage. The results verify that BV significantly attenuates the genotoxic effects of BLM on noncancerous isolated rat lymphocytes but does not diminish BLM cytotoxicity.