Toxicological effects of Tris (1,3-dichloro-2-propyl) phosphate exposure in adult male rats differ depending on the history of exposure in the neonatal period.

There is increasing concern about multiple high concentration exposure to toxins in disaster and emergency situations. However, conventional toxicology testing methods may not adequately address these situations. Thus, we assessed whether the toxic effects of exposure in the adulthood differ depending on the presence or absence of neonatal exposure to Tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) in male rats to investigate the effects of exposure history of chemicals. In the neonatal stage [postnatal days (PNDs) 1-7], animals were treated with either sesame oil (5 ml/kg/day) as a control or TDCIPP (250 mg/kg/day) dissolved in sesame oil. In adulthood (PND 101-107), animals were treated with either sesame oil (5 ml/kg/day) or TDCIPP (650 mg/kg/day). One day after the final administration, dissection was performed, and body and organ weight, hematology, blood biochemistry, and histopathology were examined. The results demonstrated that the toxic effects of TDCIPP exposure in adulthood on adrenal gland size, serum iron content, and unsaturated iron binding capacity were enhanced by TDCIPP exposure in the neonatal stage. From these findings, it was indicated that the toxic effects of TDCIPP exposure in the adult stage are affected by pediatric exposure. These results suggest that the toxic effects of high-dose and long-term unsteady exposure to chemicals in large-scale disasters may change based on the exposure history of chemicals.

Pentanoic acid induces thymic stromal lymphopoietin production through Gq/11 and Rho-associated protein kinase signaling pathway in keratinocytes.

Thymic stromal lymphopoietin (TSLP) plays an important role in allergic skin inflammation. Short-chain fatty acids (SCFAs), including pentanoic acid, are products of bacterial metabolism and are associated with allergic skin disorders. However, whether SCFAs induce TSLP production is still unclear. In this study, we evaluated the effect of SCFAs on TSLP production and found that pentanoic acid was the most efficacious of the tested SCFAs. The Gq/11 inhibitor YM-254890 and the Rho-associated protein kinase (ROCK) inhibitor Y-27632 inhibited pentanoic acid-induced TSLP production, as did transfection with Gq/11 siRNA. These results suggested that pentanoic acid-induced TSLP production was mediated by Gq/11 and ROCK, providing insights into a novel TSLP production pathway in keratinocytes. The novel mechanism of TSLP production is expected to support the development of TSLP-regulating approaches in allergic skin disorders.