ABSTRACT
PURPOSE: To evaluate protective mechanism of melatonin against radiation damage and its relationship with apoptosis in mouse jejunum. MATERIALS AND METHODS:' 168 mice were divided into 28 groups according to radiation dose and melatonin treatment. To analysis crypt survival, microcolony survival assay was done according to Withers an (l Elkind's method. To analysis apoptosis, TUNEL assay was done according to Labet-Moleur's method. RESULTS: Radiation protection effect of melatonin was demonstrated by crypt survival assay and its effect was stronger in high radiation dose area. Apoptosis index with 8 Gy irradiation was 18.4% in control group and 16.5% in melatonin treated group. After 18 Gy, apoptosis index was 17.2% in control group and 15.4% in melatonin treated group. Apoptosis index did not show statistically significant difference between melatonin treated group and control group. CONCLUSION: Melatonin shows clear protective effect in mouse jejunum against radiation damage but it.', protective effect seems not to be related with apoptosis protection effect.