Lesión de médula espinal

Artículos de revisión
Fisiopatología de la lesión medular. Revisión de literatura
Pathophysiology of spinal cord injury. A review
Sara Caballero Chacón*

Manuel Nieto-Sampedro**

Abstract
Here is shown the description of the physiological phenomena that occurs in spinal cord after
traumatic injury. Also are reviewed the molecular processes that are present in the developed
of primaryand secondary neuronal death. Likewise, cellular and molecular processes that
inhibit axonal growth and regeneration of central nervous system are reviewed. The finality of
this review is to approach the DVM to knowledge of the problem of spinal cord injury in order to
attack it from it´s molecular bases and take advantage of the information that basic research
can offer in our own benefit.
Keywords: SPINAL CORD INJURY, PRIMARY NEURONAL DEATH, SECONDARY NEURONAL DEATH, NERVE REGENERATION, ISCHEMIA, CELL TRANSPLANTS, REACTIVE
ASTROCYTES.

Resumen
Se presenta la descripción de los efectos fisiopatólogicos que ocurren en la lesión medular
por trauma y que inciden en los procesos moleculares que desencadenan muerte neuronal
primaria y secundaria. Se hace énfasis en los mecanismosmoleculares y celulares que impiden
la regeneración axonal en el sistema nervioso central. La finalidad de esta revisión es acercar
al médico veterinario al conocimiento a fondo sobre las lesiones medulares, para atenderlas
desde sus bases moleculares y aprovechar la información que brinda la investigación básica.
Palabras clave: LESIÓN MEDULAR, MUERTE NEURONAL PRIMARIA, MUERTE
NEURONAL SECUNDARIA,REGENERACIÓN NERVIOSA, ISQUEMIA, TRASPLANTES
CELULARES, ASTROCITOS REACTIVOS.

Recibido el 17 de febrero de 2004 y aceptado el 18 de agosto de 2004.
*Departamento de Fisiología y Farmacología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma
de México, México, D. F. Tel. 5622 5908 y 5622 5980; e-mail: saracachas@hotmail.com
**Departamento de Plasticidad Neural,Instituto Ramón y Cajal de Neurobiología, Av. Dr. Arce 37, CP 28002, Madrid, España.

Vet. Méx., 36 (1) 2005

75

Introduction

Introducción

R

E

ecently the pathophysiologic study of spinal
cord injury has been increased. This pathology,
mainly traumatic, is very important because
the central nervous system, unlike the peripheral nervous system, shows irreversible changes thatobstruct
nerve regeneration.
When the peripheral nervous system (i.e. sciatic
nerve, radial nerve, lumbar nerves) is injured, nerve
regeneration is possible because the trophic factors
produced by Schwann cells are up regulated. Those
cells also improve axonal growth because ensheat and
protect axon proximal stump, promoting growth and
the establishment of new connections in the target
thatrecovers sensitivity and functionality.1
In the central nervous system the process is not like
in the peripheral, because the primary injury (which
is located in the epicenter) destroys neuronal bodies.
Damage induces an ischemic process, inflammation
and primary neuronal death due the presence of
oxygen free radicals. Later, the lesion is extended and
secondary neuronal cell deathoccurres, killing more
neurons than the primary neuronal death. 2
There are many factors that obstruct the
regeneration of the central nervous system; substances
like proteoglycans and myelin derivatives are true
barriers and an impediment of axonal growth. 3,4 In a
realistic view, the study of these obstacles shows that
the damage in the central nervous system is much
more complex than putting incontact two electric
cables as before was believed in a simplistic way. In
this review are described the events that ocurr during
the lesion, but they do not occurr in a systematic way,
some of they are present at the same or different times
depending on the time or size of the injury, for an easy
comprehension they are described temporally.
Recently basic research in spinal cord injury...