Toxic effects of methylmercury, arsanilic acid and danofloxacin on the differentiation of mouse embryonic stem cells into neural cells

This study was performed to assess the neurotoxic effects of methylmercury, arsanilic acid and danofloxacin by quantification of neural-specific proteins in vitro. Quantitation of the protein markers during 14 days of differentiation indicated that the mouse ESCs were completely differentiated into neural cells by Day 8. The cells were treated with non-cytotoxic concentrations of three chemicals during differentiation. Low levels of exposure to methylmercury decreased the expression of GABAA-R and Nestin during the differentiating stage, and Nestin during the differentiated stage. In contrast, GFAP, Tuj1, and MAP2 expression was affected only by relatively high doses during both stages. Arsanilic acid affected the levels of GABA(A)-R and GFAP during the differentiated stage while the changes of Nestin and Tuj1 were greater during the differentiating stage. For the neural markers (except Nestin) expressed during both stages, danofloxacin affected protein levels at lower concentrations in the differentiated stage than the differentiating stage. Acetylcholinesterase activity was inhibited by relatively low concentrations of methylmercury and arsanilic acid during the differentiating stage while this activity was inhibited only by more than 40 microM of danofloxacin in the differentiated stage. Our results provide useful information about the different toxicities of chemicals and the impact on neural development.

Zearalenone Affects Immune-Related Parameters in Lymphoid Organs and Serum of Rats Vaccinated with Porcine Parvovirus Vaccine

Rats were administered zearalenone (ZEA) via gavage at dosages of 0, 1, 5, and 30 mg/kg for 36 days. On treatment day 8, inactivated porcine parvovirus vaccine (Vac) was injected intraperitoneally. Antibody production against porcine parvovirus was then measured as a function of ZEA treatment. Compared to the vaccine alone, ZEA treatment, with or without Vac, decreased the serum level of IgG. The level of IgM decreased in all ZEA groups at day 22, but the decrease was sustained only in the medium-dose ZEA group at day 36. The level of IgA was unchanged in the Vac only and ZEA groups at day 22, but was decreased in the 5 mg/kg ZEA plus Vac group compared to the Vac only group at day 36. The level of IgE was decreased by all doses of ZEA at day 22, but was unaffected in ZEA plus Vac groups compared to the Vac only group. The levels of IL-1 in the thymus and spleen; INF-gamma in serum; IL-2, IL-6, and IL-10 in the thymus; and IL-10 and IFN-gamma in the spleen decreased after ZEA administration. Furthermore, the levels of IL-1beta in the spleen and mesenteric lymph node, IL-1beta in the thymus, IL-2 in the thymus and spleen, IL-6 in the thymus, IL-10 and IFN-gamma in the spleen, and GM-CSF and TNF-alpha in the thymus decreased after vaccination in rats exposed to ZEA. In conclusion, these results suggest that ZEA exposure via drinking water can cause an immunosuppressive effect by decreasing immunoglobulins in serum and cytokines in lymphoid organs.

Pulsating Magnetic Field Effects on in vitro Culture of Human Osteogenic Sarcoma Cell Lines

In order to elucidate the biological effects of pulsating magnetic field in in vitro culture system we designed a pulsating magnetic apparatus using 120 Hertz, 24 Volt direct current. It can generate 63~225 Gauss in the experimental area of 90 mm petri dish, and has little thermal effect on the culture media in 37.5oC, 5% CO2. Human osteogenic sarcoma (HOS) cells were cultured in the pulsating magnetic field and the nuclear changes of cultured cells were observed routinely by hematoxylin staining, and apoptotic change was detected by ApopTag staining using both peroxidase and fluorescein labelings. Compared to the control group which formed well organized whorling pattern of HOS cell line in 3 days culture, the HOS cells cultured in the pulsating magnetic field for 12 hours or 24 hours grew irregularly and showed increased number of apoptotic cells. When the flow of pulsating magnetic field was interrupted by insertion of strong permanent magnetic bar (1000 Gauss, 5530 mm) beneath the petri dish during in vitro culture, the area of sparse pulsating magnetic field showed active proliferation and aggregation of HOS cells even in 24 hour exposure group. These data suggest that the pulsating magnetic field may play a role in inducing growth retardation and apoptosis of HOS cells. Furthermore, the hazardous effects of pulsating magnetic field can be lessened or nullified by the interruption of pulsating magnetic field with a strong permanent magnetic bar.