Hormetic effects of mild heat stress on the primary culture of mouse prefrontal cerebrocortical neurons

Abstract

Abstract 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% CO2. 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 2nd, 4th and 6th day of seeding. Methods On the 3rd, 5th and 7th 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 10th, 15th and 20th 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.