No abstract

This study aims to investigate the effects of maternal lead exposure on learning and memory ability and the protein expression of TNF-alpha and SNARE complex (SNAP-25, VAMP-2, and Syntaxin 1A) in hippocampus of mice offspring. Pb exposure was initiated from beginning of gestation to weaning. Pb acetate administered in drinking solutions was dissolved in distilled deionized water at 0.1%, 0.5%, and 1% groups, respectively. On the PND21, the learning and memory ability of mouse pups was tested by water maze test, and the Pb levels in their blood and hippocampus were also determined. The protein expression of TNF-alpha and SNARE complex in hippocampus was measured by immunohistochemistry and Western blotting. The Pb levels in blood and hippocampus of all exposure groups were significantly higher than control group (P < 0.05). In the water maze test, the performances of 0.5% and 1% groups were worse than that of control group (P < 0.05). The expression of TNF-alpha, Syntaxin 1A, and VAMP-2 was increased in Pb-exposed groups comparing control group (P < 0.05), but the expression of SNAP-25 was decreased (P < 0.05). Up-regulation of TNF-alpha and disturbance of SNARE expression in the hippocampus of pups may contribute to impairment of learning and memory ability associated with maternal Pb exposure.

The epithelium is a highly dynamic system, which plays a crucial role in the homeostasis of the intestinal tract. However, studies on the physiological and pathophysiological functions of intestinal epithelial cells (IECs) have been hampered due to lack of normal epithelial cell models. In the present study, we established a reproducible method for primary culture of mouse IECs, which were isolated from the viable small intestinal crypts of murine fetuses (on embryonic day 19), using type I collagenase and hyaluronidase in a short span of time (≤20 min). With this method, continuously growing mouse IECs, which can be subcultured over a number of passages, were obtained. The obtained cell lines formed a tight cobblestone-like arrangement, displayed long and slender microvilli, expressed characteristic markers (cytokeratin 18 and Notch-1), and generated increasing transepithelial electrical resistance and low paracellular permeability during in vitro culture. The cells also had enzymatic activities of alkaline phosphatase and sucrase-isomaltase, and secreted various cytokines (IL-1β, IL-6, IL-8, and monocyte chemoattractant protein-1), responding to the stimulation of Escherichia coli. These results show that the primary-cultured mouse IECs obtained by the method established here had the morphological and immunological characteristics of IECs. This culture system can be a beneficial in vitro model for studies on mucosal immunology and toxicology.