Effect of the denervation of porcine ovaries on dexamethasone-induced cyst formation

Previously, we have shown that the activity of noradrenergic nerve fibres increased and the steroid content changed in porcine ovaries with dexamethasone-(DXM-) induced polycystic status. To better understand the role of the ovarian nerves in the formation of cystic status, the morphology and steroidogenic activity of the ovaries of DXM-treated gilts after denervation of the gonads were investigated in this study. Ovarian denervation was performed on day 3 of the first studied oestrous cycle and then, on days 7–21 of the cycle, DXM was administered. Following neurectomy and DXM treatment, cysts, medium-sized follicles and corpora lutea were not present, while the number of small-sized follicles increased. Denervation and DXM application led to a reduction in the number of dopamine-β-hydroxylase- and/or neuropeptide Y-immunoreactive nerve fibres. The concentrations of progesterone, androstenedione, testosterone and oestradiol-17β in the follicular fluid and/or in the wall of small-sized follicles of the experimental gilts were lower than in the controls. A similar result was demonstrated for P450scc, 3β-HSD and P450arom protein contents in the small follicles. Our data showed that DXM was not able to stimulate the formation of cysts in denervated porcine ovaries, indicating that the ovarian peripheral nerves might participate in the aetiopathogenesis of polycystic status