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Journal Article 2014; 35(8): 697-702 PubMed PMID: 25702298 Citation  Keywords:  Adult, Depressive Disorder, Major:pathology, Diffusion Tensor Imaging:methods, Female, Humans, Male, Nerve Regeneration:physiology, White Matter:anatomy & histology,.   

OBJECTIVE: While increasing evidence suggests that major depressive disorder (MDD) is coincident with the altered white matter microstructure in many brain regions including the prefrontal cortex, parietal lobe, ventral tegmental area and limbic system, it remains controversial in the nature of white matter structural changes and in its relationship with depression syndrome. We believe that the age of patients and the antidepressant treatment to them would contribute to that controversy. Here in this study we explored the microstructural changes of the entire brain white matter of the adult patients with first-episode, antidepressant drug-naïve MDD.

DESIGN: We performed the diffusion tensor imaging (DTI) among a relatively large sample size of patients and age-matched control individuals (forty-one MDD patients and forty-one control subjects) and used recently developed tract-based spatial statistics to analyze the difference of mean fractional anisotropy (FA) between patients and control individuals.

RESULTS: We surprisingly found that MDD patients exhibited a significantly greater mean FA, which is used to elucidate the structural organization of the neural fibers, than control subjects in the whiter matter of the left superior longitufinal fasciculus. However, this change in the white matter of MDD patient did not correlate with depressive clinical features (HMAD, illness duration and initial age) in the present study.

CONCLUSION: Our data suggest that a potential compensatory regeneration of nerve fibers occurs in the early course of MDD development. Advanced understanding of the potential nerve fiber regeneration in the early course of MDD and its associated mechanisms will possibly shade light on a better strategy for MDD prevention and treatment....

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Journal Article 2010; 31(4): 530-537 PubMed PMID: 20802438 Citation  Keywords:  Animals, Axons:pathology, Microscopy, Electron, Nerve Regeneration:physiology, Optic Nerve:pathology, Optic Nerve Injuries:pathology, Rats,.   

OBJECTIVE: The present work was aimed at studying the ultra structural changes of the proximal (retinal) stump of the intracranially transected optic nerve of the rat for any possible regenerative ability.

METHODS: Specimens were collected one (1 wpo) and four weeks(4 wpo) after the transection and the cross sections of the stumps were studied by electron microscopy by dividing them into three zones, (1) the central zone, (2) the intermediate zone, and (3) the peripheral zone.

RESULTS: The present results showed evident morphological changes in these zones both in the 1 wpo and 4 wpo groups. The signs of degeneration were more marked in the central zone than in the peripheral zone and they were more prominent in the 1 wpo group than in the 4 wpo group. The most prominent sign of the degeneration was loss or lack of the healthy myelinated axons. The main evidence of the regenerative ability was the reappearance of the apparently healthy myelinated axonal profiles, with a parallel decrease of the non myelinated ones. This regenerative feature was more prominent peripherally and might be an indication that ischemia was the cause of optic nerve degeneration.

CONCLUSIONS: The present work revealed a clear morphological evidence of the regenerative capability of the intracranially transected optic nerve though it is considered as a part of the CNS....

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