Primary Actions Of Free Radical And Ca²⁺ Response To Electromagnetic Fields Exposed Rat-hippocampal Neurons

The investigation of electromagnetic fields(EMF) in human health risk assessment include of epidemiology,human and animals,cellular system,biochemistry and molecular biology,and biophysical mechanisms.The causal chain describes a series of sequential steps to lead to disease outcome for EMF to cause biological effect.To complete the first step,or say primary effect,the physical reaction between EMF with bio-molecules must come into being chemical reaction in organism,and then bring biological reaction.To research relationship of radical,energy and cytosolic calcium has significance to know primary effect of EMF and the sequent biological effects.In the paper,the effect of long period(48 hours) at low intensity(0.1mT,0.5mT and 1.0mT) power frequency EMF exposure and short period at high intensity(10 mT, 20mT) on rat-hippocampal neurons was investigated by evaluating the reactive oxygen species(ROS) and cytosolic Ca²⁺ concentration.Fluorescence microplate reader and Laser scanning confocal microscope are used to detect the ROS and cytosolic calcium. To make sure the communication of ROS and cytosolic calcium,H₂O₂ was added in positive control group.The results give some insight of the relationship of ROS and cytosolic calcium when IP₃R was inhibited by 2-APB.In the thesis,to get six conclusions as follows:1.ROS level at 0.1mT,0.5mT and 1.0 mT EMF have be all signification increaser(p＜0.01) than control(sham),ROS at 0.1mT and 0.5mT have be no difference (p＞0.05) than Trolox+EMF,ROS at 1.0 mT has be signification increaser(p＜0.01) than Trolox+EMF.The results suggest the long exposure to MF can enhance ROS formation.2.The short period but high intensity EMF exposure can also enhance ROS formation.ROS peak appear when exposure to 10.0 mT,the ROS peak is higher at 20.0 mT,but the results is unstable.We believe that the instant exposure to high intensity of MF bring irreversible damage to neuron.Oxidative stress will occur when ROS lever is so high.3.Long and short periods exposure both can enhance the cytosolic Ca²⁺ concentration.4.There are positive correlations between ROS level and cytosolic Ca²⁺ concentration.ROS is decrease at 0.1mT,correspondingly cytosolic Ca²⁺ concentration is low.ROS has high level at 1.0mT,10mT,20.0mT,and correspondingly cytosolic Ca²⁺ concentration is high.Cytosolic Ca²⁺ concentration is decline when Trolox is added.5.EMF exposure led to decline in mitochondrial membrane potential.It might be the reasons for the increase of intracellular ROS.6.IP₃R may play important role when ROS regulates the cytosolic Ca²⁺ concentration.Cytosolic Ca²⁺ concentration is upgraded when IP₃R activated by ROS. Cytosolic Ca²⁺ concentration is declined when Trolox is added.The pathway to store Ca²⁺ in ER and SR may be in function when ROS is little and IP₃R is inhibited.The pathway to decline Cytosolic Ca²⁺ concentration in neuron is SERCA2b,but the mechanism has not been clarified.