Quercetin alleviates splenic oxidative stress and inflammatory damage induced by long-term exposure to a mixture of phthalates in rats.

Phthalates (PEs) are environmental endocrine disruptors that can induce oxidative damage to organs, such as testes, liver and spleen. Quercetin (Que), a flavonoid phytochemical, exerts antioxidant protective potential. This study aimed to investigate the alleviating effects of Que on splenic damage induced by a mixture of three commonly used PEs (MPEs) in rats, and further elucidate the underlying mechanisms. MPEs' structural characterization was identified with FTIR, and the spectrum of MPEs exhibited broadened and overlapped absorption peaks, consistent with the superposition of signals from the individual PEs. Thirty-six SD rats were randomly divided into control group, MPEs group and MPEs + Que group. The rats in MPEs + Que group and MPEs group were treated with 16 mg/kg/d MPEs with or without 50 mg/kg/d Que. After three months of continuous intervention, the serum levels of DEHP, DBP and BBP in MPEs group and MPEs + Que group were highly significantly higher than those in control group (P < 0.01). Compared with control, MPEs reduced spleen weight (P < 0.05), increased splenic malondialdehyde (MDA) level (P < 0.01), and caused splenic pathological changes, such as white pulp atrophy, red pulp congestion, blurred boundaries, marginal zone expansion, inflammatory infiltration, hemosiderin deposition and a significant increase of macrophage (P < 0.05); as well as upregulation of splenic tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, catalase (CAT), superoxide dismutase 1 (SOD1) and heme oxygenase-1 (HO-1). Whereas, those parameters were restored in MPEs + Que group. The results indicated that long-term MPEs exposure induced splenic inflammatory damage in rats, and Que exerted a significant alleviative effect likely through its antioxidant capacity.