The role of small GTPase Rac1 in ionizing radiation-induced testicular damage

Abstract

Purpose

The main acute and late effects of ionizing radiation on living organisms are the formation of reactive oxygen species (ROS), apoptosis and DNA damage. Since the Rac1 molecule is a subunit of the NADPH oxidase enzyme, it is known to participate in the generation of ROS. The aim of this study was to investigate the role of Rac1 molecule in testicular damage induced by low (0.02 Gy), medium (0.1 Gy) and high (5 Gy) dose irradiation.

Material and method

In this study, Wistar rats (except the control group) were received whole body X-ray irradiation. Testicular tissues were removed 2 hours, 24 hours and 7 days after radiation exposure. Testicular damage was examined by hematoxylin-eosin staining and Johnsen’s score. Immunohistochemical staining and G-LISA method were used to determine Rac1 expression and activation. To evaluate the generation of ROS in the testicular tissues, intracellular ROS, superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured.

Results

Increases in testicular damage were detected in all radiation exposed groups in a dose- and time-dependent manner. Compared to the control group, Rac1 expression decreased in all irradiated groups, while Rac1 activation increased. In addition, intracellular ROS and MDA levels were increased and SOD activity levels decreased in the irradiated groups compared to the control group.

Conclusion

Our findings suggest that Rac1 has a role in the increase of intracellular ROS and lipid peroxidation which led to an increase in radiation- induced testicular damage.

Keywords:

• Ionizing radiation
• Rac1
• radiation damage
• Reactive oxygen species (ROS)
• Testis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Research Fund of the Dokuz Eylul University, project number 2017.KB.SAG.050.

Notes on contributors

Yasar Aysun Manisaligil

Yasar Aysun Manisaligil, Ph.D. Department of Medical Physics, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey

Mukaddes Gumustekin

Mukaddes Gumustekin, Prof. of Department of Pharmacology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey

Serap Cilaker Micili

Serap Cilaker Micili, Assoc. Prof. of Department of Histology and Embryology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey

Cemre Ural

Cemre Ural, Ph.D. of Department of Molecular Medicine, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey

Zahide Cavdar

Zahide Cavdar, Assoc. Prof. of Department of Molecular Medicine, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey

Gizem Sisman

Gizem Sisman, Ph.D. of Department of Medical Physics, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey

Aysegul Yurt

Aysegul Yurt, Assoc. Prof. of Department of Medical Physics, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey