Study of the ultrastructural changes in the thyroid gland of rats exposed to pulsed electromagnetic wave(PEMW)

The effects of exposure to PEMW (pulsed electromagnetic wave) on function and morphology of the thyroid gland of rats are observed. At different time points (24 h, 48 h, 96 h, 8 d) after exposure to PEMW (E = 115 kVmiddotm^-1, 12000 pulses), radioimmuno-assay was performed to observe the levels of thyroid-stimulating hormone (TSH), thyroxine (T₄) and triiodothyronine (T3) in sera of those male SD rats; the optics microscope and the transmission electron microscope were used to observe the structural changes of thyroid gland as the indicated time points respectively. The T₃ T₄ and TSH in sera all increased significantly to the peak at 24 h, then gradually decreased. Although there were no obvious changes under the optics microscope, some ultrastructural changes had been found under the transmission electron microscope in thyroid gland. Ultrastructures were obviously changed at 12 h and aggravated after 12 h until 48 h. In these rats, dilatated endoplasmic reticulum gathered with lots of protein excretion, lipid droplet and the heterochromatin gathered under the nucleus membranes were observed in follicular epithelial cells. These changes were palliated at 96 h but not recovered. PEMW can affect levels of hormones in sera and the hazard ultrastructural changes of thyroid gland. Endoplasmic reticulum is the main injured organelle