Radioprotective Effects of Amifostine, L-Carnitine and Vitamin E in Preventing Early Salivary Gland Injury due to Radioactive Iodine Treatment.

OBJECTIVE: Standard treatment of differentiated thyroid cancer includes total thyroidectomy and high-dose Radioactive Iodine Therapy (RIT) for ablation of remnant thyroid tissue. When administered systemically, RIT can cause radiation-induced damage in non-targeted normal tissues. The aim of the present study was to compare the protective effects of amifostine (AMI), LCarnitine (LC), and Vitamin E (EVIT) against high dose radioactive iodine treatment induced Salivary Gland (SG) damage using SG scintigraphy and histopathological examination. METHODS: Forty adult guinea pigs were studied. Twenty guinea pigs receive 555-660 MBq 131Iodine intraperitoneally (IP) to ablate the thyroid and impair the parenchymal function of the SGs. The animals were divided into eight groups as follows: (1) Group 1 (control): 1 mL IP PS (physiological saline); (2) Group 2: single dose of 200 mg/kg IP AMI one hour prior to 1 mL IP PS; (3) Group 3: 200 mg/kg IP LC and 1 mL IP PS for 10 days; (4) Group 4: 40 mg/kg intramuscular (IM) EVITand 1 mL IP PS for 10 days; (5) Group 5: IP RIT after premedication; (6) Group 6: Single dose of 200 mg/kg IP AMI one hour prior to RIT and IP RIT after premedication; (7) Group 7: IP RIT after premedication and 200 mg/kg IP LC for 10 days starting one day before RIT; and (8) Group 8: IP RIT after premedication and 40 mg/kg IM EVIT for 10 days starting one day before RIT. Scintigraphy was performed 1 month after treatment. SGs were examined by light microscopy and a histopathological scoring system was used to assess the degree of SG damage. RESULTS: There were significant differences in the body weight and thyroid hormone levels between the groups after treatment. CONCLUSION: The individual use of AMI, LC and EVIT for radioprotection yield different levels of protection against radioactive iodine treatment injury in SGs; however, none of the agents could provide absolute protection at the doses administered in this experimental model.

The protective effect of amifostine on radiation-induced acute pulmonary toxicity: detection by (99m)Tc-DTPA transalveolar clearances.

PURPOSE: The purpose of this study was to determine by using (99m)Tc-diethylenetriaminepentaacetic acid (DTPA) lung scintigraphy whether amifostine given before irradiation protects alveolocapillary integrity in a rabbit model. METHODS AND MATERIALS: Twenty white New Zealand rabbits were randomly divided into 4 groups: (1) control (CONT), (2) amifostine alone (AMF), (3) radiation (RAD), and (4) radiation plus amifostine (RAD+AMF). The AMF and RAD+AMF groups received amifostine. The RAD and RAD+AMF groups were irradiated to the right hemithorax with a single dose of 20 Gy using a (60)Co treatment unit. Amifostine (200 mg/kg) was given i.p. 30 min before irradiation. The (99m)Tc-DTPA radioaerosol study was performed 14 day after irradiation. RESULTS: The mean clearance rate of (99m)Tc-DTPA in control subjects was 140 +/- 21 min. The highest t((1/2)) value was noted in the RAD group (603 +/- 105 min, p = 0.001). There were no significant differences between the (99m)Tc-DTPA lung clearance rates of the CONT, RAD+AMF (238 +/- 24 min), and AMF groups (227 +/- 54 min). The mean penetration index values of CONT, RAD, AMF, and RAD+AMF are 63% +/- 1.6%, 63% +/- 2.5%, 60% +/- 2.9%, and 63% +/- 2%, respectively. CONCLUSIONS: We concluded that amifostine treatment before the lung irradiation protects the lung alveolocapillary integrity. This study confirms the protective effect of amifostine in an acute phase of radiation lung injury.