Impacts Of Low Power Density Microwaves And High Iodine On Mouse Thyroid Functions

Objective:The paper is to explore the impacts posed by long-term continuous irradiation of low power density microwaves on thyroid functions of high-iodine mice,based on which health effects of pure low-power density microwaves exposure,pure high-iodine condition,combined long-term exposure are further discussed.Methods : A total of 120 KM male mice immediately after delectation were randomly divided into four groups,including the normal control group(N),the high-iodine group(HI),the microwaves group(M),the high-iodine and microwaves combined group(HIM).All the four groups were fed with basic mouse diet(with iodine content of 0.30 ug/g);while the N and M groups were fed with iodized water,and the HI and HIM groups were fed with high-iodine water(with iodine content of 3000 ug/L).The experiment duration was 20 weeks.Continuous 24-h irradiation of microwaves(3-8GMHz,power=20?w/ cm2)was rendered to the M and HIM groups.A total of 10 eyeballs were randomly selected for blood sampling at Week 1,Week 10 and Week 20 respectively;Serum T3,T4,FT3,FT4 and TSH were measured;the weights of thyroids were measured and relative weights of thyroids were calculated.Results:(1)At Week 1,serum T3,T4,FT3,FT4 and TSH levels of the HI,M and HIM groups showed no significant difference from the N group.(2)At Week 10,the serum T4 levels were significantly increased in the HI and HIM groups than the N group;the serum levels were slightly higher in the HI and HIM groups than the N groups,showing no statistical significance;the FT3,FT4 and TSH levels of the two groups showed no significant difference from the N group.Comparison between the HI group and the HIM group showed no significant difference of T3,T4,FT3,TF4 and TSH.Comparing with the N group,the serum T3,T4,FT3,TF4 and TSH of the M group showed no significant difference.At Week 20,comparing with the N group,the serum T3 levels were reduced in the M and HIM groups,and the serum TSH levels of the HI and HIM groups were increased;while the serum THS level was significantly higher in the HI group than the HIM group;the serum T4 of the HI group showed no difference from the control group.(4)At Week 1,weights and relative weights of thyroids showed no statistical difference among the groups.At Week 10,the weights and relative weight of thyroids in the HI and HIM groups were both about 1.5 times that of the control group,while the HI group and the HIM group showed no significant intergroup difference.At Week 20,the weights and relative weight of thyroids in the HI and HIM groups were both about 2 times that of the control group,while the HI group and the HIM group showed no significant intergroup difference.Conclusion :(1)With proper iodine consumption,short-term exposure of low-density microwaves poses no impacts on thyroid functions,while long-term continuous irradiation mildly inhibits thyroid functions.(2)Under a condition of high iodine consumption,short-term irradiation of microwaves poses no impacts on thyroid functions,while long-term continuous irradiation compromises thyroid functions by inhibiting hypothalamus-pituitary-thyroid axial system.(3)A high iodine level compromises thyroid functions;autonomic regulation of thyroid is firstly activated,while hypothalamus-pituitary-thyroid axial system is started late.(4)High iodine level induces goiter under irradiation of microwaves and without microwaves irradiation,and aggravates goiter with time.Microwave irradiation does not induce goiter.