The protective effect of regucalcin against radiation-induced damage in testicular cells.
OBJECTIVE
Regucalcin (RGN), a protein broadly expressed in the male reproductive tract, has shown to have beneficial effects on spermatogenesis suppressing chemical-induced apoptosis. This study aimed to evaluate whether RGN overexpression ameliorates the spermatogenic phenotype after radiation treatment.


METHODS
Transgenic rats overexpressing RGN (Tg-RGN) and their wild-type (Wt) counterparts were exposed to a single dose of X-rays (6Gy), and at ten weeks after irradiation, the testicular status and the epididymal sperm parameters were evaluated. The expression of RGN and several cell cycle and apoptosis regulators, the enzymatic activity of caspase-3, and RGN immunostaining were also assessed.


RESULTS
Tg-RGN animals displayed higher gonadosomatic index, and augmented sperm viability and motility relatively to their Wt counterparts after irradiation, as well as higher frequency of normal sperm morphology and a diminished incidence of head-defects. The differences in reproductive parameters were underpinned by a lower rate of apoptosis, as evidenced by the reduced activity of caspase-3, lower levels of caspase-8, and increased Bcl-2/Bax ratio in the testis of Tg-RGN animals. Supporting the involvement of RGN in the anti-apoptotic response, an enhanced expression of RGN was observed in irradiated rats.


CONCLUSIONS
Transgenic-overexpression of RGN protected against radiation-induced testicular damage, which strengthens the role of this protein protecting cells from the damage of external agents. These findings also indicated that the modulation of RGN testicular levels would be a mechanism for fertility preservation in men undergoing oncological treatment.
CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
Ana M S
AM
Silva
CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
Sara
S
Correia
CNC.IBILI, University of Coimbra, Coimbra, Portugal; Biophysics Unit, Faculty of Medicine, University of Coimbra, Coimbra, Portugal; CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
João E
JE
Casalta-Lopes
CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; CNC.IBILI, University of Coimbra, Coimbra, Portugal; Biophysics Unit, Faculty of Medicine, University of Coimbra, Coimbra, Portugal; CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
Ana C
AC
Mamede
CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
José E B
JE
Cavaco
CNC.IBILI, University of Coimbra, Coimbra, Portugal; Biophysics Unit, Faculty of Medicine, University of Coimbra, Coimbra, Portugal; CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
Maria F
MF
Botelho
CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal. Electronic address: ssocorro@fcsaude.ubi.pt.
Sílvia
S
Socorro
CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal. Electronic address: cmaia@fcsaude.ubi.pt.
Cláudio J
CJ
Maia
D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases; D020169:Caspases / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects / Q000528:radiation effects; D015870:Gene Expression; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D055647:Rats, Transgenic; D013094:Spermatozoa / Q000187:drug effects / Q000528:radiation effects; D013737:Testis / Q000378:metabolism / Q000528:radiation effects*
D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D002265:Carboxylic Ester Hydrolases; C513325:Rgn protein, rat; D020169:Caspases
Male fertility preservation; Radiation therapy; Regucalcin; Testicular damage