Evidence demonstrates the bidirectional communication and regulation between the neuroendocrine and immune systems. Thyroid hormones play key roles in nervous system development and can exert influence on various immune cells contributing to pathophysiological conditions. Octyl methoxycinnamate (OMC) is one of the most commonly used UV filters, and in vitro and in vivo studies have found thyroid disrupting effects. The present study assessed whether OMC administration in mice dams during the lactational period can cause thyroid disruption and generate immunologic alterations in the offspring. Indirect exposure to the OMC (1,000 mg/kg) in the lactational period affected neurodevelopment parameters, such as delayed eye-opening and weight gain in mice of both sexes, and these alterations are corroborated by the decrease in the T4 levels present in the pups' blood. No significant changes were observed in the thymus of these pups, but the number of lymphocytes increased in the spleen of the animals exposed to OMC, similar to the animals treated with propyl-thiouracil (PTU), a well-known thyroid disruptor. OMC modulated the percentage of leukocyte populations in peripheral blood, and the number of circulating polymorphonuclear cells increased twofold. In vitro, OMC exhibited an inhibitory effect on splenocyte proliferation and IL-2 production induced by anti-CD3 antibody; however, this effect was reversed with the addition of T4 in the cell culture. In summary, the results of the present study demonstrate the influence of OMC on thyroid dysregulation and its impact on the modulation of the immune system in mice pups.
Solidago chilensis Meyen (Compositae) is a species native to South America (Brazil) popularly known as arnica. In Brazilian popular medicine, inflorescences and rhizomes of this plant have been used since the end of the 19th century to replace the exogenous and hepatotoxic Arnica montana L. in the treatment of edema and inflammatory pathologies. Although the anti-inflammatory activity of S. chilensis is evidenced in the literature, there is a lack of studies with enriched fractions or compounds isolated from it. The objective of the current study was to characterize phytochemically and to evaluate the pharmacological action in vivo and in vitro of the crude extract and the different fractions (hexane, dichloromethane, acetal, butanolic, and aqueous) isolated from the inflorescence of S. chilensis. The inflorescence crude extract (ScIE) and fractions were administered by intraperitoneal route to mice at different doses. In an LPS-induced pleurisy model, inhibition of leukocyte influx was observed for the ScIE and all fractions tested, as compared to controls. Dichloromethane (ScDicF), butanolic (ScButF), and aqueous (ScAquF) were selected for further analysis as they showed the best inhibitory effects in leukocyte migration and inflammatory cytokine and chemokine production: TNF-α, CXCL1/KC, CXCL2/MIP-2, and CCL11/eotaxin-1. In LPS-stimulated J774A.1 cell line, ScIE and the ScDicF exhibited an inhibitory effect on nitric oxide (NO) production and downmodulated the COX-2 expression; ScAquF failed to modulate NO production and COX-2 expression. In phytochemical analysis, HPLC-UV-DAD chromatograms of ScDicF and ScAquF showed the main peaks with UV spectrum characteristics of flavonoids; chlorogenic acid and isoquercetin were the most present phytochemicals identified in the ScAquF, and a high number of n-alkanes was found in ScHexF. Our study was the first to address biological effects and correlate them to phytochemically characterized fractions from inflorescences of S. chilensis.
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