MENU
Anatomy
Anesthesiology
Biochemistry
Biomedical Informatics
Biophysics
Cell Biology
Clinical Cases
Dentistry
Dermatovenerology
Emergency Medicine
Family Medicine
Forensic Medicine
Gynecology and Obstetrics
Histology and Embryology
History of Medicine
Human Genetics
Hygiene
Infectious Diseases
Internal Medicine
Medical Deontology and Philosophy
Medical Psychology
Microbiology and Immunology
Neurology
Occupational Medicine
Oncology
Ophthalmology
Orthopaedics
Otorhinolaryngology
Pathology
Pathophysiology
Pediatrics
Pharmacology and Experimental Toxicology
Physical and Rehabilitation Medicine
Physiology
Psychiatry
Radiology
Social Medicine
Surgery
Toxicology
Research papers
Clinical research paper
Preclinical research paper
Sponsored articles
Archive » 2000 » 1 » | Archive » Medical field » Fields » Pathophysiology »

Regeneration of Injured Peripheral Rat Nerve without Cellular Support Distally from the Site of Injury

 
Abstract:

This post is also available in: enEnglish slSlovenščina (Slovenian)

The following hypotheses were examined: 1. Rapid initial elongation of the regenerating axons in crushed nerves observed even in the absence of distal cell support is later slowed down or stops altogether. 2. If, in addition, Schwann cell proliferation in the proximal nerve stump is prevented, the reduction of the axon elongation rate during the prolonged absence of cell support beco­mes more severe. 3. Prior collateral sprouting which exposes neurons to higher NGF concentrations has a sti­mulatory effect on axon regeneration in the absence of cell support, therefore the axon regeneration rate is less affected. The rapid initial rate of sensory axon growth through acellular distal nerve segments decrea­ses 8 days after axonotmesis. During the next three weeks, retraction of leading axons towards the site of the lesion occurs and the number of axons distal to the crush site is reduced. Axon growth is resumed thereafter, but at a much lower rate. Mitomycin application, which pre­vents Schwann cell proliferation in the proximal stump, does not prevent the initial rapid axon elongation in the absence of cell support, but later the axons retract all the way to the crush site and no further growth occurs over 6 weeks. Exposure of regenerating axons to NGF during collateral sprouting enhances the initial elongation rate in the absence of cell sup­port, delays cessation of growth and prevents axon retraction. The number of axons distal to the lesion site remains high. Schwann cells in the distal nerve segment provide and maintain a favourable growth sub­stratum for regenerating axons during a prolonged time period after nerve injury. Growth promoting substances secreted by Schwann cells seem to enable elongation or prevent retrac­tion of axons even in the case of deterioration of the growth substratum. In the presence of good growth substratum, these substances moderately enhance the elongation rate of rege­nerating sensory axons.

Authors:
Srpčič Matevž

Keywords:
sural nerve - injuries, nerve regeneration, Schwann cells - drug therapy, mitomycins, axons, rats

Cite as:
Med Razgl. 2000; 39: 3–21.

Download PDF >>
© 2022 Društvo Medicinski razgledi | Na vrh strani / To top ↑