Comparative analysis of myelinated periarterial nerves of human ovaries at different stages of ontogenesis

Objective . To compare the myeloarchitectonics of ovarian nerves of fetuses, newborns, middle-aged women, and those of presenile and senile ages. Materials and methods . The study was conducted on 158 neurovascular complexes of the ovaries of fetuses at 32–40 weeks, as well as of newborns, middle-aged women, and those of presenile and senile ages. In this study, histological methods were used, i.e., the Krutsay method for staining myelin fibers. The data are presented as medians and interquartile ranges. Differences between continuous variables were determined using the Mann-Whitney test. Spearman's rank correlation was used to evaluate the connections between variables. The P-value < 0.05 was considered statistically significant. Results . The myeloarchitectonics of ovarian nerves is characterized by age-related, quantitative, and qualitative changes. The myelination onset of ovarian nerves is determined in fetuses at 37 weeks' gestation with the occurrence of myelinated fibers of small diameter. In newborns, an increase in the total number of fibers and the occurrence of medium-diameter fibers are observed. In middleaged women, an increase in the total number of myelinated fibers is observed due to the occurrence of large-diameter myelinated fibers. In women of presenile and senile ages, involutional changes in the myelin component in ovarian nerves are revealed in a decrease in the total number of myelinated fibers of all groups. Compared to middle-aged women, the total number of myelinated fibers in nerves decreases by almost 25%. In presenile and senile ages, a significant decrease in the total number of myelinated fibers in nerves is observed. Conclusion . The study of age-related dynamics of the composition of myelinated fibers in nerves characterizes the development of ovarian nerves in particular and autonomic nerves in general. Knowledge of anatomical and physiological features of the ovaries at the stage of ontogenesis is especially important for both morphologists and practitioners and opens up new prospects in the prevention and treatment of diseases of the female reproductive system.