Assessment of the effects of single and combined exposure to microplastics and environmental pollutants on the nervous system and neurobehavior

在第一年，我的目标是研究口服聚苯乙烯纳米塑料（PS-NPs）对大鼠脑功能和行为的影响。5周龄Sprague Dawley雄性大鼠口服45 nm PS-NPs （Polysciences, Warrington， PA， USA）或无菌水，剂量为10 mg/kg或50 mg/kg，每周3次，连续4周。9周龄时，对大鼠进行开阔场测试（OFT）、新物体识别（NOR）、高架迷宫（EPM）和筑巢（NC）等行为测试。采集海马，采用实时RT-PCR和免疫组织化学方法检测神经元活性指标、突触蛋白、炎症因子、神经营养因子、胶质细胞标志物。高剂量ps - nps暴露大鼠表现出焦虑样行为和认知缺陷。高剂量ps - nps暴露大鼠的神经元活性指标（cFos，早期生长反应1）、突触蛋白（PSD-95, synaptophysin）、神经营养因子（BDNF， NGF）显著降低，而炎症因子（il - 1- β, tnf - α）和小胶质细胞标志物（Iba1）显著升高。我们的研究结果表明，口服暴露于PS-NPs通过改变大鼠海马突触区神经元-胶质-免疫细胞相互作用诱导学习、记忆障碍和焦虑样行为。

In this first year, I aimed to investigate the effect of oral administration of polystyrene nanoplastics (PS-NPs) on brain functions and behaviors in rats. Five-week-old Sprague Dawley male rats were given 45 nm PS-NPs (Polysciences, Warrington, PA, USA) or sterile water by oral administration at doses 10 mg/kg or 50 mg/kg thrice per week for four weeks. At the age of 9-week-old, behavioral tests such as open field test (OFT), novel object recognition (NOR) test, elevated plus maze (EPM) test and nest construction (NC) test were performed. The hippocampus was collected to detect neuronal activity indicators, synaptic proteins, inflammatory cytokines, neurotrophic factors, glial markers using real-time RT-PCR and immunohistochemical analyses. Hight dose PS-NPs-exposed rats showed anxiety-like behavior and cognitive deficit. Neuronal activity indicators (cFos, early growth response 1), synaptic proteins (PSD-95, synaptophysin), neurotrophic factors (BDNF, NGF) were significantly lower whereas inflammatory cytokines (IL1-beta, TNF-alpha) and microglial marker (Iba1) were significantly higher in high dose PS-NPs-exposed rats. Our results indicate oral exposure to PS-NPs induced learning, memory impairment and anxiety-like behavior by altering neuron-glia-immune cells interaction at synaptic regions in the rat hippocampus.