Open Access

ARTICLE

Ultrastructural changes of the olfactory bulb in manganesetreated mice

VIRGINIA VILLALOBOS¹, ERNESTO BONILLA^2,4,*, ALAN CASTELLANO³, ERNESTO NOVO¹, RALPH CASPERSEN⁴, DEBORA GIRALDOTH¹, SHIRLEY MEDINA-LEENDERTZ⁴

1. Departamento de Biología, Facultad Experimental de Ciencias, Universidad del Zulia, Maracaibo, Venezuela.
2. Instituto de Investigaciones Clínicas “Dr. Américo Negrette”, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.
3. Instituto de Investigaciones Biológicas, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.
4. Centro de Investigaciones Biomédicas (CIB-IVIC Zulia), Estado Zulia, Maracaibo, Venezuela.
* Address correspondence to: Ernesto Bonilla. E-mail: embonilla2008@yahoo.com

BIOCELL 2009, 33(3), 187-197. https://doi.org/10.32604/biocell.2009.33.187

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.

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