Parvalbumin-positive GABAergic interneurons are increased in the dorsal hippocampus of the dystrophic mdx mouse
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Duchenne muscular dystrophy (DMD) is characterized by variable alterations of the dystrophin gene and by muscle weakness and cognitive impairment. We postulated an association between cognitive impairment and architectural changes of the hippocampal GABAergic system. We investigated a major subpopulation of GABAergic neurons, the parvalbumin-immunopositive (PV-I) cells, in the dorsal hippocampus of the mdx mouse, an acknowledged model of DMD. PV-I neurons were quantified and their distribution was compared in CA1, CA2, CA3, and dentate gyrus in wild-type and mdx mice. The cell morphology and topography of PV-I neurons were maintained. Conversely, the number of PV-I neurons was significantly increased in the mdx mouse. The percent increase of PV-I neurons was from 45% for CA2, up to 125% for the dentate gyrus. In addition, the increased parvalbumin content in the mdx hippocampus was confirmed by Western blot. A change in the hippocampus processing abilities is the expected functional counterpart of the modification displayed by PV-I GABAergic neurons. Altered hippocampal functionality can be responsible for part of the cognitive impairment in DMD.
KeywordsDuchenne muscular dystrophy Mutant mouse strain Dystrophin Immunohistochemistry Dentate gyrus
We are grateful to Dr. Daniele Nosi for providing his competent skills for the preparation of digital microphotographs. We thank also Dr. Alberto Granato and Dr. Francesco Lolli for the careful reading of manuscript and helpful suggestions.
Conflict of interest statement
The authors declare that they have no conflict of interest.
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