title: Ultrastructural changes of the olfactory bulb in manganese-treated mice.
abstract: The effect of manganese toxicity on the ultrastructure of the olfactory bulb was evaluated. Male albino mice were injected intraperitoneally with MnCl2 (5 mg/Kg/day) five days per week during nine weeks. The control group received NaCl (0.9%). The olfactory bulbs of five mice from each group were processed for transmission electron microscopy after 2, 4, 6 and 9 weeks of manganese treatment. On week 2, some disorganization of the myelin sheaths was observed. After 4 weeks, degenerated neurons with dilated cisternae of rough endoplasmic reticulum and swollen mitochondria appeared. A certain degree of gliosis with a predominance of astrocytes with swollen mitochondria, disorganization of the endomembrane system, dilation of the perinuclear cisternae and irregularly shaped nuclei with abnormal chromatin distribution were observed after 6 weeks. Some glial cells showed disorganization of the Golgi apparatus. On week 9, an increase in the number of astrocytes, whose mitochondrial cristae were partially or totally erased, and a dilation of the rough endoplasmic reticulum were found. Neurons appear degenerated, with swollen mitochondria and a vacuolated, electron dense cytoplasm. These changes seem to indicate that the olfactory bulb is sensitive to the toxic effects of manganese.
authors.affiliation: Departamento de Biología, Facultad Experimental de Ciencias, Universidad del Zulia, Maracaibo, Venezuela.
authors.forename: Virginia
authors.initials: V
authors.lastname: Villalobos
authors.forename: Ernesto
authors.initials: E
authors.lastname: Bonilla
authors.forename: Alan
authors.initials: A
authors.lastname: Castellano
authors.forename: Ernesto
authors.initials: E
authors.lastname: Novo
authors.forename: Ralph
authors.initials: R
authors.lastname: Caspersen
authors.forename: Debora
authors.initials: D
authors.lastname: Giraldoth
authors.forename: Shirley
authors.initials: S
authors.lastname: Medina-Leendertz
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000648:ultrastructure; D002712:Chlorides / Q000633:toxicity*; D018870:Endoplasmic Reticulum, Rough / Q000187:drug effects* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000187:drug effects / Q000648:ultrastructure; D008297:Male; D017895:Manganese Compounds; D051379:Mice; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects / Q000648:ultrastructure; D009457:Neuroglia / Q000187:drug effects / Q000648:ultrastructure; D009474:Neurons / Q000187:drug effects* / Q000648:ultrastructure; D009830:Olfactory Bulb / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; C025340:manganese chloride