Progesterone effects on neuronal ultrastructure and expression of microtubule-associated protein 2 (MAP2) in rats with acute spinal cord injury.

GONZÁLEZ SL.; LÓPEZ-COSTA JJ.; LABOMBARDA F.; GONZALEZ DENISELLE MC.; GUENNOUN R.; SCHUMACHER M.; DE NICOLA AF.

CELLULAR AND MOLECULAR NEUROBIOLOGY.

SPRINGER/PLENUM PUBLISHERS

Lugar: USA; Año: 2009 vol. 29 p. 27 - 39

0272-4340

Following acute spinal cord injury progesterone modulates several molecules essential for motoneuron function, although the morphoogical substrates for these effects are unknown. The present study analyzed morphoogical changes in motoneurons distal to the lesion site from rats with or without progesterone treatment. We employed electron microscopy to study changes in nucleus and cytoplasm and immunohistochemistry for MAP2 for changes in cytoskeleton. After spinal cord injury, the nucleoplasm appeared more finely dispersed resulting in reduced electron opacity and the nucleus adopted an eccentric position. Changes of perikarya included dissolution of Nissl bodies and dissociation of polyribosomes (chromatolysis). After progesterone treatment for 3 days, the deafferented motoneurons now presented a clumped nucleoplasm, a better preserved rough endoplasmic reticulum and absence of chromatolysis. Progesterone partialy prevented development of nuclear eccentricity. Whereas 50% of injured motoneuron presented nuclear eccentricity only 16% presented this phenotype after receiving progesterone. Additionally, injured rats showed reduced immunostaining for MAP2 in dendrites, pointing to cytoskeleton abnormalities, whereas progesterone treatment attenuated the injury-induced loss of MAP2. Our data indicated that progesterone maintained in part neuronal ultrastructure, attenuated chromatolysis, and preclude the loss of MAP2, suggesting a protective effect during the early phases of spinal cord injury.