Morphology of the Sensitive and Motor Neuron Populations, Forming a Sciatic Nerve in Norm and at Its Cutting in Adult Rats
Aim of investigation is a study of the sensitive and motor neuron population, participating in a sciatic nerve (SN) in norm forming and on the 300 days after its cutting in adult rat.
Materials and Methods. Experimental investigation is accomplished on white breedless male-rats (n=16) with a mass of 200—250g. The right SN was cut at the upper third of a femur level in the control and experimental group animals. A method of retrograde marking with a Mini-Ruby fluorescent stain is used for a study of the neuron populations, forming a SN. A marking was made through a proximal SN stump in a control group, and separately, through a proximal and distal stump in experimental group. The longitudinally oriented serial sections of the cerebrospinal nodes with a 25 mkm thickness and longitudinal and transverse serial sections of the spinal cord with a 50 mkm thickness were prepared at a freezing microtome. A calculation of the marked neurons with the visible nuclei was made in each section.
Results. It is established in norm that a population of motoneurons, forming a SN, is located in segments L4—L6, and a population of the sensitive ones is located in segments L3—L6. A ratio of motor and sensitive neurons is 1:2.49.
The groups of surviving, regenerating and reserve neurons are distinguished in experiment (in 300 days). A group of surviving motoneurons was 37.41%, and a group of the sensitive ones was 15.34% of the populations in norm. More than 50.64% of the motor and 11.07% of the sensitive neurons were in those with a cicatrix. A group of reserve neurons included 49.36% of the motor and 88.93% of the sensitive neurons.
Conclusion. The motor and sensitive neuron populations, forming a SN in norm, are quantitatively defined, and a higher potential to regeneration in the motor neurons compared to sensitive ones is revealed.
