The effects of metylprednisolone and halofuginone in preventing proximal esophageal and hypopharengeal fibrosis in rats delivered radiotherapy to their head and neck region

İn this study we assesed the effects of halofuginone and metylprednisolone on hypopharengeal and esophageal stricture which can be developed later following the radiation to the head and neck of the rats.The study was carried out with the winstar rats weighted between 150-250 gr. Rats were divided randomly in to four groups each consisted of 10 rats and 18 Gy radiation was given to the head and neck regions of all rats except control group. The subjects were classified as follow: Group 1 (Control Group); radiation and drug were not given. Group 2 (Radiation Group); only radiation was applied without any drug. Group 3 (Halofuginone Group); 100 µg/kg/day halofuginone was given intraperitonealy for 30 days following the radiation. Group 4 (Steroid Group); 1mg/kg/day metylprednisolone was given intramuscular for 30 days following radiation. Rats were killed by the high dose of ketamine in all groups 90 days after the radiation application and sections of proximal esophagus and hypopharenx were harvested avoiding to spoil anatomical integrity. These sections were examined for the fibrosis, fibroblast proliferation, vascularization, epithelial atypia, necrosis, polymorph nuclear leucocytes, mononuclear cells and stenosis index by light microscope and hydroxiproline levels by biochemically.Fibrosis, epithelial atypia and hydroxyproline levels were significantly higher in radiation group compared with the control group (p<0,05). We didn?t observed fibrosis in both halofuginone and control groups. Fibrosis was also significantly decreased in steroid group than radiation group (p<0,05). Epithelial atypia and hydroxyproline levels were decreased in both halofuginone and steroid groups compared with the radiation group (p<0,05). The differences of stenosis index score between the groups were not significant statistically (p<0,05). Vascularization was similiar in all groups.Results show that halofuginone and steroid application following radiation have decreased the fibrosis in esophagus and hypopharenx but this event has been more manifest by halofuginone. We think that espacially halofuginone seems as a drug which can be used safely to prevent from fibrosis.