The changes of the Thyroid Gland caused by formaldehyde and protective effects of melatonin and Vitamin C

In this study, 75 albino rats of Wistar Albino strain were employed randomly in 8 groups. As control group 5 rats were used as the rest divided into 7 groups. Rats in group II were used as sham. Rats in group III and IV were injected formaldehyde intraperitoneally at doses of 10 and 15 mg/kg everyday excluding weekends. Rats in group V and VI daily received 100 mg/kg vitamin C in addition to formaldehyde injection. Rats in group VII and VIII daily received 25 mg/kg melatonin in addition to formaldehyde.After four weeks of experiment, rats were sacrificed by taking intracardiac blood. Plasma levels of TSH, fT3 and fT4 were determined. TSH levels were higher in melatonin given groups. There was a significant difference between Group VIII and the Groups IV and V. Also fT4 levels were higher in melatonin and vitamin C given groups compared to control, but they weren?t statistically significant. There was no difference in WST-1 analysis.In the light microscopic examination, degenerative changes and mast cell infiltration were observed mostly in group IV.These changes decreased in rats which received antioxidants mostly in the melatonin group. While mast cell infiltration was decreased in melatonin given groups, it was increased in vitamin C given groups. Although follicular size was bigger in melatonin given groups but there was no statistical difference.In conclusion, it was seen that changes caused by exposure to formaldehyde were decreased in rats which received melatonin and vitamin C.