Targeted neuronal lesion induced by photosensitizing dyes.
Free radical-induced phototoxicity mediated by laser irradiation was investigated in the rabbit facial nerve. Azure-C, mesoporphyrin, or the dye conjugated to the protein carrier horseradish peroxidase were injected into the levator alae nasi muscle. Two to 7 days after uptake and laser exposure, nerve sections showed varying degrees of cellular modifications including: severe membrane degradation and associated lipid peroxide granules, distended mitochondria, and mitochondrial loss. Immunoblots of homogenates from treated nerves revealed specific changes in neurofilament and myelin basic protein. The site specific damage produced in vivo by photosensitizing dye resembles abnormalities in aging neurons and in Batten's disease, both hypothesized to be cases of free radical-peroxidation reactions. These reactions differ from those found in transection and crush lesions.
Wang-Bennett
L T
LT
Department of Otorhinolaryngology and Communicative Sciences, Baylor College of Medicine, Houston, TX 77030.
Liebl
D J
DJ
Bennett
G N
GN
D000818:Animals; D001370:Axonal Transport; D001399:Azure Stains / Q000633:toxicity*; D001933:Brain Stem / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D005152:Facial Muscles / Q000294:innervation; D005154:Facial Nerve / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D005609:Free Radicals; D006735:Horseradish Peroxidase; D009474:Neurons / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects / Q000648:ultrastructure; D011817:Rabbits; D011838:Radiation-Sensitizing Agents / Q000633:toxicity*; D013194:Staining and Labeling
D001399:Azure Stains; D005609:Free Radicals; D011838:Radiation-Sensitizing Agents; D006735:Horseradish Peroxidase; C045363:Azure C