Acta Medica Leopoliensia (Dec 2016)
Structural organization and morphometric parameters the inferior olivary complex in the prenatal period of human ontogenesis
Abstract
Aim. To determine the structure and morphometric parameters of the inferior olivary complex nuclei and nerve cells forming it in embryos and human fetuses at different gestational age. Materials and Methods. A morphological and histological study of 230 human embryos and fetuses from 6-7 to 39-40 weeks of fetal development was carried out. The material for the study was obtained after abortion; no malformations of the central nervous system were found. Also, studies were done on stillborn fetuses that died of causes not related to brain or spinal cord diseases in relatively healthy mothers. Dissection was held in Vinnitsia regional postmortem office and maternity hospitals of Vinnitsia. The research design and materials are in compliance with the fundamental bioethical norms of the Helsinki Declaration adopted by the 59 General Assembly of the World Medical Association in 2008. Results and Discussion. In human embryos at 6-7 weeks of gestation the inferior olivary complex is presented by a curved serrated plate. In the human fetuses at 8-9 weeks an additional medial accessory olivary nucleus is revealed. Three nuclei of the inferior olivary complex were found in human fetuses at 10-11 weeks of gestation. In the human fetuses at 20-21 weeks, the primary olivary nucleus changes the curved shape of the plate for a convoluted one. During embryogenesis neuroblasts change shape from spherical to polygonal. Area of the primary olivary nucleus is the largest in human fetuses from 12 to 15 and from 30 to 40 weeks; the smallest - in human fetuses at 20-21 weeks of fetal development. The area of the right medial accessory olivary nucleus is increased by 80.5% from 10-11 to 39-40 weeks; the left - by 87,2% (p <0,01). The area of the right dorsal accessory olivary nucleus is increased by 76.0% from 10-11 to 39-40 weeks; the left - by 78,3% (p <0,01). The average area of neuroblasts of the primary olivary nucleus increases most intensely in human fetuses at 17-18 weeks and 20-21 weeks (by 45.6% and 50.3%, respectively); the medial accessory olivary nucleus in human fetuses increases in the 17-18 and 25-26 weeks (by 22.2% and 50.9%); the dorsal accessory olivary nucleus in human fetuses at 17-18 weeks and 20-21 weeks (by 48.7% and 37,8%) (p <0,01). The average area of the nuclei of the neuroblasts of the primary olivary nucleus most intensely increases in human fetuses at 17-18 and 25-26 weeks (by 22.3% and 26.8%, respectively); the medial accessory olivary nucleus in human fetuses - at 17-18 weeks (by 24, 7%); the dorsal accessory olivary nucleus in human fetuses - at 14-15 weeks (by 31,1%) (p <0,01). Conclusions. The developed three nuclei of the inferior olivary complex were found in human fetuses at 10-11 weeks of fetal development. The nerve cells in the inferior olivary complex in the process of embryogenesis change their shape from spherical to oval (17-18 weeks), and from oval to polygonal (37-38 weeks). The age periods of the increase in the area of the inferior olivary complex nuclei and the middle area of the neuroblasts and their nuclei were established.
