Simultaneous determination of five constituents of areca nut extract in rat plasma using UPLC-MS/MS and its application in a pharmacokinetic study.

Areca nuts have been used as a traditional Chinese medicine (TCM) for thousands of years. Recent studies have shown that it exhibits good pharmacological activity and toxicity. In this study, the pharmacokinetics of five major components of areca nut extract in rats were investigated using a highly sensitive ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-MS/MS) method. Arecoline, arecaidine, guvacoline, guvacine, and catechin were separated and quantified accurately using gradient elution with mobile phases of (A) water containing 0.1 % formic acid-10 mM ammonium formate, and (B) methanol. The constituents were detected under a timing switch between the positive and negative ion modes using multiple reaction monitoring (MRM). Each calibration curve had a high R2 value of >0.99. The method accuracies ranged -7.09-11.05 % and precision values were less than 14.36 %. The recovery, matrix effect, selectivity, stability, and carry-over of the method were in accordance with the relevant requirements. It was successfully applied for the investigation of the pharmacokinetics of these five constituents after oral administration of areca nut extract. Pharmacokinetic results indirectly indicated a metabolic relationship between the four areca nut alkaloids in rats. For further clarification of its pharmacodynamic basis, this study provided a theoretical reference.

N-acetylcysteine rescues meiotic arrest during spermatogenesis in mice exposed to BDE-209.

Deca-bromodiphenyl ethers (BDE-209) has been widely used in electronic devices and textiles as additives to flame retardants. Growing evidence showed that BDE-209 exposure leads to poorer sperm quality and male reproductive dysfunction. However, the underlying mechanisms of BDE-209 exposure caused a decline in sperm quality remains unclear. This study aimed to evaluate the protective effects of N-acetylcysteine (NAC) on meiotic arrest in spermatocytes and decreased sperm quality in BDE-209-exposed mice. In the study, mice were treated with NAC (150 mg/kg BW) 2 h before administrated with BDE-209 (80 mg/kg BW) for 2 weeks. For the in vitro studies, spermatocyte cell line GC-2spd cells were pretreated with NAC (5 mM) 2 h before treated with BDE-209 (50 µM) for 24 h. We found that pretreatment with NAC attenuated the oxidative stress status induced by BDE-209 in vivo and in vitro. Moreover, pretreatment with NAC rescued the testicular histology impairment and decreased the testicular organ coefficient in BDE-209-exposed mice. In addition, NAC supplement partially promoted meiotic prophase and improved sperm quality in BDE-209-exposed mice. Furthermore, NAC pretreatment effectively improved DNA damage repair by recovering DMC1, RAD51, and MLH1. In conclusion, BDE-209 caused spermatogenesis dysfunction related to the meiotic arrest medicated by oxidative stress, decreasing sperm quality.

Vitamin C supplementation rescued meiotic arrest of spermatocytes in Balb/c mice exposed to BDE-209.

Deca-brominated diphenyl ether (BDE-209) is a ubiquitous industrial chemical as brominated flame retardant (BFRs). Exposure to BDE-209 has been clearly associated with male reproductive disorders. However, the meiotic arrest mechanism of spermatocytes exposed to BDE-209 is still unclear. The present work aimed to explore the protective effect of vitamin C on BDE-209-induced meiotic arrest of spermatocytes and its possible mechanism. Vitamin C (100 mg/kg BW) was administered to BDE-209-exposed (80 mg/kg BW) male Balb/c mice once daily by intraperitoneal injection for 2 weeks. Our results showed that vitamin C played male reproductive protection effects as showed by attenuated BDE-209-induced testicular damage, and reduced sperm abnormality rate. Vitamin C also attenuated BDE-209-induced increase in SOD and MDA in testes and GC-2 spd cells. Moreover, vitamin C promoted meiotic prophase in BDE-209-induced mice, with suppressed γ-H2AX, restored DMC1, RAD51, and crossover marker MLH1 levels, and prevented BDE-209-induced DNA impairment. In addition, vitamin C supplementation also interfered with BDE-209-induced upregulation of testicular H3K4me3 through inhibition of KDM5s capacity and decreasing ferrous ion concentration. Furthermore, ferrous sulfate pretreatment could partially restore the expression of H3K4me3 via maintaining the concentration of ferrous ions. Taken together, vitamin C exerts a potential therapeutic agent for preventing BDE-209-induced reproductive toxicity with meiotic arrest, which is attributed to its antioxidant and electron donor properties, as well as, modulation of ferrous ion levels and demethylation of H3K4me3.