Ginkgo biloba extract protects against tartrazine-induced testicular toxicity in rats: involvement of antioxidant, anti-inflammatory, and anti-apoptotic mechanisms.

The use of additives, especially colorants, in food and pharmaceutical industry is increasing dramatically. Currently, additives are classified as contaminants of emerging concern (CECs). Concerns have been raised about the potential hazards of food additives to reproductive organs and fertility. The present study investigates the reproductive toxicity of tartrazine (TRZ), a synthetic colorant, in male rats and aims to explore the curative effect of Ginkgo biloba extract (EGb) against TRZ-induced testicular toxicity. Twenty-four rats were divided into four groups: the control (0.5 ml distilled water), the EGb group (100 mg/kg EGb alone), the TRZ group (7.5 mg/kg TRZ alone), and the TRZ-EGb group (7.5 mg/kg TRZ plus 100 mg/kg EGb). The doses were administered orally in distilled water once daily for 28 days. Toxicity studies of TRZ investigated testicular redox state, serum gonadotropins, and testosterone levels, testicular 17 ß-hydroxysteroid dehydrogenase activity, sperm count and quality, levels of inflammatory cytokines, and caspase-3 expression as an apoptotic marker. Also, histopathological alterations of the testes were examined. TRZ significantly affected the testicular redox status as indicated by the increase in malondialdehyde and the decrease in reduced glutathione, superoxide dismutase, and catalase. It also disrupted serum gonadotropins (follicle stimulating hormone and luteinizing hormone) and testosterone levels and the activity of testicular 17ß-hydroxysteroid dehydrogenase. Additionally, TRZ adversely affected sperm count, motility, viability, and abnormality. Levels of tumor necrosis factor-α, interleukin-1ß, interleukin-6, and expression of caspase-3 were increased in the testes. Histopathological examination of the testes supported the alterations mentioned above. Administration of EGb significantly ameliorated TRZ-induced testicular toxicity in rats. In conclusion, EGb protected against TRZ-induced testicular toxicity through antioxidant, anti-inflammatory, and anti-apoptotic mechanisms.

Apoptosis and glucocorticoid-related genes mRNA expression is modulated by coenzyme Q10 supplementation during in vitro maturation and vitrification of bovine oocytes and cumulus cells.

Oocyte in vitro maturation (IVM) and vitrification procedures lead to detrimental effects on the overall oocyte quality. The addition of antioxidants during IVM, such as the coenzyme Q10 (Q10), has been demonstrated to positively impact on the cumulus-oocyte complexes due to its role in protection from oxidative damage and modulating gene transcription. Furthermore, glucocorticoids (GC) regulate gene transcription, energy metabolism and apoptosis during the early steps of reproduction. In this sense, most GC actions are mediated by the glucocorticoid receptor (NR3C1), a transcription factor. However, the specific roles of GC in ovarian physiology and oocyte maturation are still unknown. In this regard, a better knowledge on the expression of GC-related and apoptosis-related genes during IVM and cryopreservation procedures could potentially benefit the refinement of assisted reproductive techniques in the bovine species. The present study aims to explore the expression of NR3C1 mRNA in fresh and vitrified bovine oocytes and cumulus cells in response to Q10 (50 µM), and the effect of cortisol addition (0.25 µM, 0.5 µM) on the expression of NR3C1. We also studied the mRNA expression of NR3C1-related genes belonging to the GC regulation pathway, such as hydroxysteroid dehydrogenases (HSD11B1; HSD11B2), immunophilins (FKBP4; FKBP5), signal transducers and activators of transcription (STAT3; STAT5A), the mineralocorticoid receptor (NR3C2), and to the apoptosis pathway, such as the anti- (BCL2) and pro-apoptotic (BAX) mRNA transcripts in oocytes and cumulus cells 1) after IVM, and 2) after vitrification, both in presence or absence of Q10 supplementation during IVM. Our results show that there is an increase in the NR3C1 receptor expression after vitrification of oocytes, but not after exogenous cortisol supplementation during IVM. In addition, Q10 reduces the mRNA expression of HSD11B1 and FKBP5 in oocytes at levels of immature oocytes (HSD11B1 mRNA expression also in cumulus cells), and the BAX:BCL2 ratio mRNA expression. After vitrification in the presence of Q10, HSD11B2 mRNA expression increases in cumulus cells, while HSD11B1 and BAX:BCL2 mRNA expression decreases significantly both in oocytes and cumulus cells. In conclusion, our results show for the first time the effect of IVM, vitrification and Q10 supplementation on the mRNA relative expression of GC-related and apoptosis genes, and the effect of vitrification in the protein expression of NR3C1.