Sara Volpe

Effects of epigallocatechin-3-gallate (EGCG) on in vitro maturation and fertilization of porcine oocytes

The beneficial properties of green tea and especially of its principal active polyphenol, epigallocatechin-3-gallate (EGCG), have led to an increased demand for dietary supplements with highly enriched EGCG concentrations. In order to investigate the possible reproductive-related consequence of EGCG supplementation, the effects of this catechin on in vitro maturation (IVM) and fertilization (IVF) of oocyte, using the pig as experimental model, were examined. In the first series of experiments EGCG, at concentrations ranging from 0 to 25 microg/ml, was added during in vitro maturation of pig oocytes. EGCG had no effect on nuclear maturation of pig oocytes and on fertilization traits considered after IVF at any of the doses tested. By contrast, a significant (p<0.05) decrease in the number of embryos that developed to blastocysts following parthenogenetic activation was recorded when 25 microg/ml EGCG was added to IVM medium; in addition this catechin concentration significantly (p<0.05) inhibited progesterone production by cumulus cells after 48 h of culture. When induction of sperm capacitation was performed in presence of EGCG, a significantly lower percentage of spermatozoa showing a Hsp70-capacitated pattern and a significant reduction of sperm H(2)O(2) production were evident at a concentration of 25 microg/ml EGCG (p<0.05). During gamete coincubation EGCG reduced, in a dose response manner, the number of reacted spermatozoa suspended in fertilization medium and increased the number of sperm bound to ZP. Supplementation of 10 microg/ml EGCG during IVF significantly increased the fertilization rate while higher EGCG concentrations (25 microg/ml) decreased the percentage of fertilized oocytes (p<0.05). In conclusion, our data suggest that high EGCG concentrations could affect in vitro maturation and fertilization in pig; it cannot be totally excluded that excessive EGCG concentrations could induce reproductive-related consequences also in vivo.

COMPARATIVE IMMUNOLOCALIZATION OF HEAT SHOCK PROTEINS (HSP) -60, -70, -90 IN BOAR, STALLION, DOG AND CAT SPERMATOZOA

Heat shock proteins (Hsp)-60, -70 and -90 are important testis chaperones that fulfil several functions during sperm cell maturation. In post-meiotic cells, their expression may change or may be undetectable and in some species it may be evident in mature spermatozoa. The aims of this study were to verify whether Hsp60, -70 and -90 are present in the sperm, and to compare their localization in boar, stallion, cat and dog spermatozoa by immunofluorescence. Hsp-60 immunoreactivity was detected in sperm midpiece in all the species examined. In stallion sperm, Hsp70 signal was localized in the sub-equatorial band, whereas immunoreactivity was evident on the neck of dog spermatozoa and on both neck and sub-equatorial region of cat spermatozoa. In agreement with our previous observations, a triangular fluorescent signal in the equatorial segment of fresh boar sperm was detected. Hsp90 immunoreactivity was present in different portions of sperm tail: in the midpiece of both boar and cat spermatozoa and in the neck and throughout the tail in dog and stallion spermatozoa, respectively. When capacitation and acrosome reaction were induced in boar, stallion and dog spermatozoa, no changes in both Hsp60 and -90 were recorded by either Western blot or immunofluorescence. After induction of acrosome reaction, a Hsp70 redistribution in boar spermatozoa and an increased percentage of stallion spermatozoa showing the post-acrosomal signal were observed although no changes were recorded by Western blot; in dog spermatozoa, no changes in Hsp70 were found by Western blot and immunofluorescence after capacitation and acrosome reaction.

Estradiol-17β, Progesterone and Testosterone Plasma Concentrations during Estrus in the Bitch

Rota, A., Veronesi, M.C., Volpe, S., Riccardi, A. and Battocchio, M., 2007. Estradiol-17β, progesterone and testosterone plasma concentrations during estrus in the bitch. Veterinary Research Communications, 31(Suppl. 1), 197–199

Assessment of Some Morphofunctional Characteristics of Flow-Cytometrically Sorted and Stained Boar Spermatozoa

The possibility to predetermine the sex of offspring is one of the most ambitious targets of reproductive biotechnology. Besides the scientific implication in human medicine (sex-linked hereditary diseases), gender preselection of farm animals would have the most evident impact. For specific breeding purposes it may be convenient to have either males or females. Herd productivity can be increased by the selection of animals with the sex that fits the best with performance. Sex preselection could furthermore be successfully applied to the preservation of endangered species. The possibility to determine sex is primarily based on: (1) the use of PCR in blastomers taken from preimplantation embryos, characterized by technical and ethical problems, and (2) the separation of chromosome-X bearing spermatozoa from chromosome-Y bearing spermatozoa by cytofluorimetry on the basis of their different relative DNA content (Johnson and Pinkel, 1986; Johnson and Welch, 1999). The use of sexed spermatozoa represents in theory a simple procedure (Seidel and Garner, 2002); however, the real possibility of separating enough X-bearing spermatozoa from Y-bearing spermatozoa for routine artificial insemination in sow under field conditions is far from being a reality (Johnson, 2002; Rath et al., 2003). During the sexing procedure sperm cells undergo chemical, physical and electrical stresses that can induce sperm damage. The objective of this study was to determine the effect of the staining procedure, with or without flow cytometry, on boar sperm membrane integrity, mitochondrial activity and blastocyst development in vitro. The evaluation of these parameters was also performed on stained and sorted semen after 24 h of storage at 17◦C.