RFamide-related peptide (RFRP)-3 reduces luteinising hormone (LH) secretion in rodents. Stress has been shown to upregulate the expression of the RFRP gene (Rfrp) with a concomitant reduction in LH secretion, but an effect on expression of the gonadotrophin-releasing hormone (GnRH) gene (Gnrh1) has not been shown. We hypothesised that lipopolysaccharide (LPS)-induced stress affects expression of Rfrp, the gene for kisspeptin (Kiss1) and/or Gnrh1, leading to suppression of LH levels in rats. Intracerebroventricular injections of RFRP-3 (0.1, 1, 5 nmol) or i.v. LPS (15μgkg-1) reduced LH levels. Doses of 1 and 5 nmol RFRP-3 were then administered to analyse gene expression by in situ hybridisation. RFRP-3 (5 nmol) had no effect on Gnrh1 or Kiss1 expression. LPS stress reduced GnRH and Kiss1 expression, without affecting Rfrp1 expression. These data indicate that LPS stress directly or indirectly reduces Gnrh1 expression, but this is unlikely to be due to a change in Rfrp1 expression.
This study was conducted to investigate the effect of docosahexanoic acid (DHA) supplementation in BioXcell extender on the quality of frozen-thawed bull semen. Twenty-four ejaculates were collected from three bulls (eight from each bull). Ejaculates with motility ≥70% and normal morphology ≥80% were extended into BioXcell extender to which 0 (control), 3, 5, 10 or 15ngmL(-1) DHA was added. The supplemented semen samples were incubated at 37°C for 15min for DHA uptake by spermatozoa. Later, samples were cooled for 2h at 5°C and packaged into 0.25-mL straws, frozen in liquid nitrogen for 24h and subsequently thawed for evaluation. Results are presented as percentages ± s.e.m. Supplementation with DHA at 3ngmL(-1) significantly improved sperm functional parameters including sperm motility, normal morphology, viability, acrosome integrity and membrane integrity when compared with other supplemented groups and the control. Lipid peroxidation increased as the incorporation of DHA supplementation increased. In conclusion, 3ngmL(-1) concentration of DHA resulted in superior quality of frozen-thawed bull spermatozoa and is suggested as the optimum level of DHA to be added into BioXcell extender.
Ectopic implantation of donor testis cell aggregates in recipient mice results in de novo formation or regeneration of testis tissue and, as such, provides a unique invivo model for the study of testis development. However, currently the results are inconsistent and the efficiency of the model remains low. This study was designed to: (1) examine several factors that can potentially improve the consistency and efficiency of this model and (2) explore the use of ultrasound biomicroscopy (UBM) for the non-invasive invivo evaluation of implants. Testis cell aggregates, containing ~40% gonocytes, from 1-week-old donor piglets were implanted under the back skin of immunodeficient mice through skin incisions using gel matrices or through subcutaneous injection without using gel matrices. The addition of gel matrices led to inconsistent tissue development; gelatin had the greatest development, followed by collagen, whereas agarose resulted in poor development. The results also depended on the implanted cell numbers since implants with 100×106 cells were larger than those with 50×106 cells. The injection approach for cell implantation was less invasive and resulted in more consistent and efficient testis tissue development. UBM provided promising results as a means of non-invasive monitoring of implants.
Despite its important role in numerous physiological functions, including regulation of appetite and body weight, immune function and normal sexual maturation, raised leptin levels could result in significant damaging effects on sperm. The adverse effects of leptin on the male reproductive system result from its direct actions on the reproductive organs and cells instead of the hypothalamus-pituitary-gonadal axis. Binding of leptin to the receptors in the seminiferous tubular cells of the testes increases free radical production and decreases the gene expression and activity of endogenous enzymatic antioxidants. These effects are mediated via the PI3K pathway. The resultant oxidative stress causes significant damage to the seminiferous tubular cells, germ cells and sperm DNA leading to apoptosis, increased sperm DNA fragmentation, decreased sperm count, increased fraction of sperm with abnormal morphology, and decreased seminiferous tubular height and diameter. This review summarises the evidence in the literature on the adverse effects of leptin on sperm, which could underlie the often-reported sperm abnormalities in obese hyperleptinaemic infertile males. Although leptin is necessary for normal reproductive function, its raised levels could be pathologic. There is, therefore, a need to identify the cut-off level in the serum and seminal fluid above which leptin becomes pathological for better management of leptin associated adverse effects on male reproductive function.