Background Hormesis is an adaptive response of a biological system to low dose of stressors. It exerts beneficial effects to enable the cells and organisms to sustain the unfavourable conditions. Mild heat stress is one of the widely studied hormetic agents having antiageing and lifespan prolonging effects. In order to study the effect of mild heat stress on the primary culture of mouse prefrontal cerebrocortical neurons with reference to ageing-associated degenerative alterations the present investigations were carried out. Study design The prefrontal cerebrocortical neurons of E17 day mouse embryo were cultured on poly- l -lysine coated coverslips and fed with neurobasal medium supplemented with B-27 at 37 °C and 5% CO 2 . The neurons were divided into two groups: control group and mild heat stress group. The neurons from the control group were incubated at 37 °C without any heat stress. The neurons from the mild heat stress group were subjected to hyperthermic stress of 38 °C for 30 min on 2 nd , 4 th and 6 th day of seeding. Methods On the 3 rd , 5 th and 7 th day of incubation, viability was studied by calcein-AM and propidium iodide assay and cell death assay was carried out by lactate dehydrogenase (LDH) assay. The surviving neurons were enumerated on 10 th , 15 th and 20 th day of incubation by live cell imaging. All microscopic studies were carried out by observer blinding. Results It was observed that there was higher percentage of viable neurons and lower percentage of degenerating neurons in the mild heat stress group than the control. The difference was highly significant ( p < 0.001). Conclusion Mild heat stress (38 °C for 30 min on every alternate day up to 6 days of incubation) exerts hormetic effects on the primary culture of mouse prefrontal cerebrocortical neurons by delaying the degenerative alterations.

中文翻译：

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轻度热应激对小鼠前额叶脑皮质神经元原代培养的促效作用

背景激惹是生物系统对低剂量应激源的适应性反应。它发挥有益作用，使细胞和生物体能够承受不利条件。轻度热应激是一种广泛研究的具有抗衰老和延长寿命作用的激素。为了研究轻度热应激对小鼠前额叶脑皮质神经元原代培养的影响，参考与衰老相关的退行性改变，进行了本研究。研究设计 E17 天小鼠胚胎的前额叶脑皮质神经元在聚赖氨酸包被的盖玻片上培养，并在 37 °C 和 5% CO 2 下用补充有 B-27 的神经基础培养基喂养。神经元分为两组：对照组和轻度热应激组。对照组的神经元在没有任何热应激的情况下在 37°C 下孵育。轻度热应激组的神经元在接种的第2、4和6天经受38℃的高温应激30分钟。方法在培养的第3、5、7天，用钙黄绿素-AM和碘化丙啶测定法研究细胞活力，乳酸脱氢酶(LDH)测定法进行细胞死亡测定。通过活细胞成像在孵育的第10天、第15天和第20天计数存活的神经元。所有显微研究均通过观察者盲法进行。结果观察到，与对照组相比，轻度热应激组有较高的存活神经元百分比和较低的退化神经元百分比。差异非常显着（p < 0.001）。