Expression of prostate glycoconjugates in the stallion and castrated horse.

This article investigates the types of glycoconjugates produced by the epithelium of prostate glands in stallions and castrated horses, with the aim of understanding if these molecular patterns might be influenced by sex hormones and, potentially, contribute to the fertilization process.

Methodology

In this study, lectin histochemical procedures are used in conjunction with enzymatic digestion and deglycosylation treatments. These processes allow to discover and analyze the sugar molecules of the glycoconjugates present in the prostate cells of the studied animals.

The authors also utilized antibodies specifically designed to target 5 and 13-16-cytokeratin, a marker for epithelial basal cells. This provides further information on the cell types within the prostate glands.

Findings in the Stallion

In stallions, the glycoconjugates identified in the prostate glands presented different types of sugar residues:

• α-Glu/Man, α-Fuc and β-Gal were included in both O- and N-linked oligosaccharides.
• β-GalNAc, GlcNAc, and α-Gal were linked to O-glycoproteins.
• β-Gal and β-GalNAc moieties were found subterminal to sialyl residues.

Specialized lectins that target sialic acid revealed the presence of Neu-5Ac(α2,3-6)-β-Gal or Neu5Ac(α2,6)-β-GalNAc sequences in both N- and O-bound glycoproteins.

Findings in the Castrated Horse

The prostate glandular cells of the castrated horse expressed several of the same sugar moieties as the stallions, such as α-Glu/Man, α-Gal, and GlcNAc. However, there were also distinct patterns:

• β-D-GalNAc was only detected subterminal to sialic acid.
• β-D-Gal-(1-3)-D-GalNAc was found in N-linked glycans.
• β-D-Gal-(1-4)-D-GlcNAc and Neu5Acα2,6Gal/GalNAc were noted only in O-glycoproteins.

Implications and Conclusions

The data suggest that glycoconjugate patterns may be impacted by sex hormones, given the different patterns observed in the stallions and the castrated horses. Furthermore, no specific lectin labelling of basal cells was found in either group, but these cells stained more intensely in the castrated horse, indicating that they are androgen responsive. Lastly, given the presence of these glycoconjugates in prostatic secretions, the authors theorize that they may have a role in remodelling the sperm surface. This could occur both during sperm transit through the male genital tract and post-ejaculation in the seminal plasma, potentially affecting stallion fertility.