Hyperthermia Combined With Radiation On Embryonic Neural Developmental Toxicity And Brain Heat Shock Protein

Background The central nervous system development ( brain above all ) is sensitive especially to outside stimulation. The abnormality of conformation and behavior will appear very easily when suffering outside bad environment. The content of brain proteins and change of HSPs can reflect exactly the degree of brain differentiation and damage. At present, the data is short about the effect of hyperthermia united with radiation on the central nervous system development, especially brain HSPs and other proteins. Objective To study the relation between the toxicity of embryonic nerve development made by hyperthermia united with radiation and expression of brain proteins of earlier period embryo and HSPs. To reveal the mechanism of the abnormality caused by hyperthermia united with environment poison from protein level. And to offer a reliable idea for human prepotency and prevention of the abnormality of nerve system development. Methods the rats who are pregnant for 8 or 9 days received respectively total body irradiation for one time by 60Co (-ray, and the dosage of irradiation for two times is 1.0 Gy. When the rats are pregnant for 10 days the temperature of rat anus is respectively kept at 37(0.5℃, 41(0.5℃, 42(0.5℃, in warming boxes. and lasted for 2, 3, 4, 5 minutes. After the pregnant rats are left warming boxes for two hours, 5 rats selected randomly from each team are executed by cervical vertebra luxation. The content of brain proteins and HSP70 of embryo is analyzed with western dot blot and Lowry method. When the rats are pregnant for 18 days, 10 rats selected randomly from each team are executed by cervical vertebra luxation, and to observe the abnormality of embryonic nerve system. And let another 10 of each team to born young rats naturally, and observe their body development, physio-development, nerve reflect, study and memory and other nerve behavior. Results The toxicity is increased markedly when hyperthermia combined with irradiation, and hyperthermia intensity and action time shows positive relativity. The rats who are pregnant for 8 days were treated by hyperthermia with irradiation, and physio-development, forepart reflect, sensory function, activity ability, study and memory of their son is more lower notably than control team (P<0.01). If hyperthermia lasted longer (>minutes), hyperthermia and irradiation have complex action, and the harmful effects on nerve system development of embryo are strengthened. At embryonic earlier period, hyperthermia with irradiation can depress the content of brain proteins (P<0.01), and induce synthesis of HSP70, and there is no significant difference between the combined effect group and single high temperature group and single irradiation group. Conclusion There is certain relativity to synthesis of brain proteins and induction of HSP70 when hyperthermia combined with irradiation to produce toxicity to nerve development at molecular level. The change rule of the content drop of embryo brain proteins and the synthesis induction of HSP70 is basically consistent with hyperthermia temperature, lasting time of hyperthermia, irradiation and hyperthermia with irradiation to nerve development and nerve behavior.