Introduction and Objectives
To investigate the effects of vitamin E and melatonin on gamma ray induced damage in testes of rats.
Material and Methods
This study was conducted on 40 male Wistar type rats, weighing between 200 and 250 g, aged between 10 and 12 weeks. The rats were divided into 4 groups, each including 10 rats. Total body radiation was applied with 90 cm, 90% isodose curve using Cobalt 60 apparatus (Picker ATC C9). Thirty-two cGy/minute gamma radiation was applied to an area of 40×40 cm of where 5 rats were placed. The period of exposure time was 11 minutes 30 seconds, and a total of 360 cGy gamma radiation was administered in each session. Following radiation procedure, Group 1 was administered intraperitoneal Vit E (100 mg/kg/day), Group 2 received melatonin (100 mg/kg/day) and Group 3 rats were administered saline (100 ml/kg/day). In Group 4 rats, intraperitoneal saline (100 ml/kg/day) was administered without any radiation procedure. Testes were removed after 5 days of drug administration and were analyzed to measure malondialdehyde (MDA) levels and histopathologic injury. Lipid peroxidation was measured by the method of Ohkawa et al and testicular injury and spermatogenesis were graded as described by Johnsen et al. Mann-Whitney U test was used in the comparison of histopathologic tissue damage points and MDA levels between groups and p < 0.05 was accepted significant. Spearman correlation analysis was used in the analysis of the correlation between histopathologic tissue damage and MDA levels in each group.
Tissue MDA level measured in rats receiving melatonin did not show significant difference when compared to control group (p > 0.05) (Table 1). Similarly there was no significant tissue injury on histopathological examination between melatonin administered and control groups. However, both tissue MDA level and tissue injury were found to be significantly increased in groups which were administered vitamin E and serum physiologic compared to the control group (p < 0.05).
Table 1.Tissue MDA levels and histopathologic scores in groups
|Groups||MDA (nmol) (Mean±SD)||Histopathologic scores (Mean±SD)||Correlation (r)|
|G1(Radiation+Vit E)||4.9±0.1 (a)||5.1±0.5 (d)||0.623|
|G2 (Radiation+Melatonin)||3.5±0.6 (b)||6.1±0.7 (e)||0.782|
|G3 (Radiation+SP)||5.9±0.3 (c)||4.2±0.7 (d)||0.584|
|G4 (Only SP)||3.4±0.3 (b)||7.7±0.5 (e)||0.771|
Different superscripted letters in the same column indicate statistical significance between groups. MDA: malondialdehyde, VitE: Vitamin E, SP: Serum Physiologic, G: Group
Melatonin displays a remarkable tissue protective effect by inhibiting the damage mediated by free radicals after radiation. The same effect could not be obtained with Vitamin E. Thus, the cytoprotective effect of melatonin can be of value in preserving testicular functions after radiation procedure.
© 2009 European Association of Urology. Published by Elsevier Inc. All rights reserved.