Potential novel biomarkers for diabetic testicular damage in streptozotocin-induced diabetic rats: nerve growth factor Beta and vascular endothelial growth factor.
BACKGROUND
It is well known that diabetes mellitus may cause testicular damage. Vascular endothelial growth factor (VEGF) and nerve growth factor beta (NGF-β) are important neurotrophic factors for male reproductive system.


OBJECTIVE
We aimed to investigate the correlation between testicular damage and testicular VEGF and NGF-β levels in diabetic rats.


METHODS
Diabetes was induced by streptozotocin (STZ, 45 mg/kg/i.p.) in adult rats. Five weeks later testicular tissue was removed; testicular VEGF and NGF-β levels were measured by ELISA. Testicular damage was detected by using hematoxylin and eosin staining and periodic acid-Schiff staining, and apoptosis was identified by terminal-deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL). Seminiferous tubular sperm formation was evaluated using Johnsen's score.


RESULTS
In diabetic rats, seminiferous tubule diameter was found to be decreased; basement membrane was found to be thickened in seminiferous tubules and degenerated germ cells. Additionally, TUNEL-positive cells were increased in number of VEGF+ cells and levels of VEGF and NGF-β were decreased in diabetic testes. Correlation between VEGF and NGF-β levels was strong.


CONCLUSIONS
These results suggest that the decrease of VEGF and NGF-β levels is associated with the increase of the apoptosis and testicular damage in diabetic rats. Testis VEGF and NGF-β levels could be potential novel biomarkers for diabetes induced testicular damage.
Department of Biochemistry, Dokuz Eylul University, 35340 Izmir, Turkey.
Ali Rıza
AR
Sisman
Department of Physiology, Dokuz Eylul University, 35340 Izmir, Turkey ; Division of Behavioral Physiology, Department of Physiology, School of Medicine, Dokuz Eylul University, 35340 Izmir, Turkey.
Muge
M
Kiray
Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA ; Department of Psychiatry, Mayo Clinic Health System, Waycross, GA 31501, USA.
Ulas Mehmet
UM
Camsari
College of Natural and Applied Sciences, Department of Biotechnology, Ege University Bornova, 35920 Izmir, Turkey.
Merve
M
Evren
College of Vocational School of Health Services, School of Medicine, Dokuz Eylul University, 35340 Izmir, Turkey.
Mehmet
M
Ates
College of Physical Therapy and Rehabilitation, Dokuz Eylul University, Balcova, 35340 Izmir, Turkey.
Basak
0000-0002-4178-2235
B
Baykara
Department of Physiology, Dokuz Eylul University, 35340 Izmir, Turkey ; Division of Behavioral Physiology, Department of Physiology, School of Medicine, Dokuz Eylul University, 35340 Izmir, Turkey.
Ilkay
I
Aksu
Department of Physiology, Dokuz Eylul University, 35340 Izmir, Turkey.
Guven
G
Guvendi
Department of Physiology, Dokuz Eylul University, 35340 Izmir, Turkey ; Division of Behavioral Physiology, Department of Physiology, School of Medicine, Dokuz Eylul University, 35340 Izmir, Turkey.
Nazan
0000-0002-2348-7427
N
Uysal
D000818:Animals; D017209:Apoptosis; D015415:Biomarkers / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000150:complications / Q000378:metabolism*; D008297:Male; D020932:Nerve Growth Factor / Q000378:metabolism*; D017208:Rats, Wistar; D013311:Streptozocin; D013733:Testicular Diseases / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D013737:Testis / Q000378:metabolism* / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D015415:Biomarkers; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D013311:Streptozocin; D020932:Nerve Growth Factor