Progesterone effects on neuronal ultrastructure and expression of microtubule-associated protein 2 (MAP2) in rats with acute spinal cord injury.
(1) Following acute spinal cord injury, progesterone modulates several molecules essential for motoneuron function, although the morphological substrates for these effects are unknown. (2) The present study analyzed morphological 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 the microtubule-associated protein 2 (MAP2) for changes in cytoskeleton. (3) 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 partially prevented development of nuclear eccentricity. Whereas 50% of injured motoneurons showed 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. (4) 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.
González
Susana L
SL
Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Obligado 2490, 1428, Buenos Aires, Argentina.
López-Costa
Juan José
JJ
Labombarda
Florencia
F
González Deniselle
Maria Claudia
MC
Guennoun
Rachida
R
Schumacher
Michael
M
De Nicola
Alejandro F
AF
D000208:Acute Disease; D000818:Animals; D002466:Cell Nucleolus / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009046:Motor Neurons / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure*; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000378:metabolism* / Q000473:pathology*
C489787:MAP2 protein, rat; D008869:Microtubule-Associated Proteins; D011374:Progesterone