Fine needle aspiration cytology (FNAC) as a useful technique to evaluate seasonal variations of spermatogenesis in Cervids: relationships with histology and sperm quality

Abstract

This study was aimed at addressing the question whether Fine Needle Aspiration Cytology (FNAC) may be used as a reliable method to evaluate spermatogenesis and its seasonal variations in wild deer. No previous studies have been carried out about this topic and only qualitative correlations have been performed between cytological pattern and open testicular biopsy, the gold standard method for spermatogenesis assessment. Furthermore, due to the annual pattern of recrudescence and involution of spermatogenesis, deer could be used as an optimal model system to investigate mechanisms that regulate testicular activity. Furthermore, I aimed to explore which kind of relationships occur between germ cells, Sertoli cells and sperm quality on the basis of the hypothesis that fully active spermatogenesis during the breeding season should be related with high sperm quality. To achieve these objectives, samples post-mortem from Iberian red deer stags were collected during the breeding season and out of the breeding season. Histological analyses were performed in order to evaluate whether FNAC is a reliable method for quantifying spermatogenesis. Then, testicular cytological patterns were correlated with sperm analysis in order to evaluate their relationships. Finally, preliminary data are reported about reproductive biology and the application of FNAC in vivo on Sardinian red deer, an endemic and endangered subspecies of Sardinia and Corse