Histological investigation of effects of apocynin on testicular damage caused by radiation

Objective: The aim of this study is to investigate the effect of apocynin on rat testis damage which is caused by exposure to radiation by histochemically, immunohistochemically, electron microscopically and biochemically. Method: In our study, 35 Wistar albino male rats (n=7) were divided into 5 groups; 1-Control group: normal adlibitum fed group, 2-Sham group: 5 days ip. saline given group, 3-Apocynin group: 5 days ip. 20 mg / kg / day apocynin dissolved in saline given group, 4-Radiation group: single dose of 10 Gy scrotal radiation group, 5-Apocynin + Radiation group: 5 days before irradiation the group receive ip. 20 mg / kg / day apocynin saline and after a single dose of 10 Gy scrotal radiation applied 24 hours after the last dose of ip. 20 mg / kg / day apocynin. All groups were sacrificed 24 hours after irradiation. Hematoxylin & Eosin (H&E), Periodic Acid Sciff (PAS) and Masson Tricrom stainings were made for light microscopic examinations. Johnson's scoring was performed on testis sections besides seminiferous tubule diameter and height, seminiferous tubule basal membrane thickness' were measured. TUNEL, active caspase-3 immunohistochemistry was used to evaluate apoptosis; ZO-1 and Occludin immunohistochemical staining were made for intracellular tight junction complexes. Testicular tissue was evaluated ultrastructurally. Glutathione peroxidase (GPx), superoxide dismutase (SOD), and malondialdehyde (MDA) levels were measured in tissue homogenates for biochemical assays. Results : Seminiferous tubules, regularly sorted spermatogenic serial cells, seminiferous tubule diameters in normal thickness, seminiferous tubule epithelial height and basal membrane structures were observed normal in control, sham and apocynin groups in light microscopic and electron microscopic examinations. Germ cell loss, interstitial inland connective tissue growth was detected in the radiation group. Johnsen's score, seminiferous tubule diameter and seminiferous tubule epithelium height were decreased and thickening in the seminiferous tubule basal membrane was found. In the apocynin+radiation group, ameleration in the histomorphology of the testis was observed. As a result of the immunohistochemical studies, it was found that increase in number of TUNEL positive stained cells and active caspase-3 immunopositive cells in seminiferous tubules, number of ZO-1 immunpositive and occludin immunoreactive cells decreased in the radiation group compared to the control group. In the apocynin + radiation group, it was found that the number of TUNEL positive and active caspase-3 immunpositive cells decreased and number of ZO-1 and occludin immunoreactive cells were increased similar to the control group sections. Biochemically, it was observed that apocynin administration increased GPx and SOD levels and decreased MDA levels when compared to the injury group. Conclusion: It has been concluded that apocynin has positive protective (amendatory) effects by reducing tissue damage, apoptosis and oxidative stress in the testis damage caused by radiation.