Quantitative study of total and nociceptive nerve fibres in the human vulva

Chronic pain affects 20% of the adult population, particularly the elderly, and worsens cognitive impairment. Chronic pain includes conditions such as arthritis, neuropathic pain, or certain sexual dysfunctions. Based on this clinical relationship with vulvodynia, we conducted a study on CGRPergic innervation in the dorsal horn of the spinal cord and the female external genitalia in different age groups.Immunohistochemistry was performed against calcitonin gene-related peptide (CGRP) in the lumbosacral enlargement and vulva of adult (60, 70 years) and elderly (84, 85 years) human cadaveric donors. Results were analyzed using QuPath to quantify nerve profiles in vulva and CGRP+ boutons in dorsal horn nuclei. An increase in CGRP innervation was observed in laminae I, II and V (ρ=0,359, sig.=0,189) in older ages.In the studied sample, these data do not correlate with CGRPergic population density in the vulva. Additionally, we present a morphometric study of the peripheral innervation of female external genitals.