Sialic acid in human testis and changes with aging
G. Gheri A , D. Vichi A , G. D. Zappoli Thyrion B , L. Bonaccini A , G. B. Vannelli A , M. Marini A and E. Sgambati A C DA Department of Anatomy Histology and Forensic Medicine, University of Florence, Policlinic of Careggi, Viale Morgagni 85, 50134 Florence, Italy.
B Department of Medicine, University of Florence, Policlinic of Careggi, Viale Pieraccini 18, 50134 Florence, Italy.
C Department of Health Sciences, University of Molise, Via De Sanctis, 86100 Campobasso, Italy.
D Corresponding author. Email: eleonora.sgambati@unimol.it
Reproduction, Fertility and Development 21(5) 625-633 https://doi.org/10.1071/RD08292
Submitted: 11 December 2008 Accepted: 31 March 2009 Published: 18 May 2009
Abstract
The aim of the present study was to investigate the distribution of the glycoconjugates sialoderivatives in the human testis. Orchidectomy specimens from men aged 18–30 years (Group 1) and from men aged 70–93 years (Group 2) were obtained at autopsy. The study was performed using digoxigenin-labelled lectins, namely Maackia amurensis II lectin (MAA), Sambucus nigra agglutinin (SNA) and Arachis hypogaea lectin (PNA), in addition to enzymatic and chemical treatments (neuraminidase, KOH–neuraminidase, mild oxidation–neuraminidase, mild oxidation–KOH–neuraminidase, strong oxidation–neuraminidase, strong oxidation–KOH–neuraminidase), to characterise the different glycosidic linkages of the sialoderivatives and to obtain information regarding their structure. In all Group 2 samples, sialic acids linked α-2,3 to galactose and α-2,6 to galactose/N-acetyl-d-galactosamine (Gal/GalNAc), revealed by MAA and SNA, respectively, were observed in testicular interstitial tissue and in the lamina propria. Sialic acid linked α-2,6 to Gal/GalNAc was detected in only some samples from Group 1. After treatment, PNA showed structural changes and/or the gradual disappearance of sialic acid linked to d-galactose-β(1–3)-N-acetyl-d-galactosamine in testicular components with aging. These findings indicate that changes in the metabolism of sialoderivatives in the testis could be related to morphofunctional changes in various testicular components typical of this organ during aging. This suggests that sialoderivatives are important in the functionality of the mature testis in men, as well as its involution.
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