The morphology and neuronal-glial correlations of the spinal cord posterior horns of human embryos

Abstract

Background: This research examines the morphology and neuronal-glial correlations of human spinal cord posterior horns formations in the embryonic period of ontogenesis. Methods: 29 human embryos with a gestational age of 5-8 weeks were involved in the investigation, without visible damages and abnormalities in the development of the brain and spinal cord. Anatomical, histological, immunohistochemical, morphometric and statistical methods were used. Results: The glial index in 5-6-week human embryos in the posterior horns of cervical segments made 1.6, in thoracic segments – 1.4, in lumbar segments – 1.5, and in sacral segments – 1.3. In 6-7-week human embryos, on the lateral surfaces of the neural tube between alar and basal plates, the sulcus limitans is still preserved. The glial index in 7-8-week human embryos of posterior horns of cervical segments made 1.7, in thoracic segments – 1.5, in lumbar segments 1.6, and in sacral segments – 1.4. In 7-8-week embryos, the basal and alar plates are not distinguished anymore, that is why the terminal sulcus is absent. Conclusions: The glial index of the posterior horns of all the segments along with the spinal cord increases by the 6th-7th week, and remains unchanged by the beginning of the gestational period (before the 8th week).