Effects of endosulfan isomers on cytokine and nitric oxide production by differentially activated RAW 264.7 cells.

Endosulfan is an organochlorine insecticide comprised of two isomers: endosulfan-α and endosulfan-ß. Endosulfan exposure has been shown to elevate some inflammatory factors, such as nitric oxide (NO) and tumor necrosis factor (TNF), in animals or cultures of animal cells. Because the two endosulfan isomers can vary in their biological activities, the goal of this study was to determine if individual endosulfan isomers differentially impact production of NO or TNF by the mouse macrophage cell RAW 264.7 at non-cytotoxic levels. We found elevated TNF with exposure to endosulfan-α (not endosulfan-ß), but only at concentrations that were cytotoxic (≥100 µM), whereas neither endosulfan isomer altered baseline levels of NO at any concentration up to 300 µM. In interferon (IFN)-γ-activated cultures, NO levels were significantly suppressed by either endosulfan isomer at 10 µM (the lowest concentration examined), whereas only endosulfan-ß significantly lowered TNF levels at non-cytotoxic concentrations. In lipopolysaccharide (LPS)-activated cultures, both endosulfan isomers significantly reduced NO, but not TNF, at non-cytotoxic concentrations. These results suggest that the endosulfan isomers have some capacity to alter inflammatory responses differentially, particularly with IFN-γ stimulation.

Time- and dose-dependent effects of ethanol on mouse embryonic stem cells.

Ethanol is a common solvent used with mouse embryonic stem (mES) cells in protocols to test chemicals for evidence of developmental toxicity. In this study, dose-response relationships for ethanol toxicity in mES cells were examined. For cells maintained in an undifferentiated state, ethanol significantly reduced viable cell numbers with estimated half maximal inhibitory concentrations of 1.5% and 0.8% ethanol after 24 and 48h, respectively, observations which correlated with significantly increased expression of apoptotic markers. For cells cultured to induce cardiomyocyte formation, up to 0.5% ethanol during the first two days failed to alter the outcome of differentiation, whereas 0.3% ethanol for 11 days significantly reduced the fraction of cultures containing contracting areas, an observation that correlated with significantly reduced cell numbers. These results suggest that ethanol is not an inert solvent at concentrations that might be used for developmental toxicity testing.