OBJECTIVES:

In order to investigate the effects of alteration in masticatory activity on the cell population, the consequences of the mash diet on the amount of astrocytes in CA1 (Ammon's horn 1) of the hippocampus were evaluated. In addition, the impacts of diet and possible changes associated with the enriched environment and neuropathological processes that may appear during aging were considered.

MATERIALS AND METHODS:

Female Swiss albino mice were divided into temporal windows of 6, 12 and 18 months. These animals were distributed in groups and received pelleted (PF) or mash (MF) feed, being raised in an enriched or standard environment. With the mentioned age reached, encephalic material was processed for immunohistochemistry of glial fibrillary acidic protein. With the aid of an optical fractionator, astrocytes were quantified in CA1, with variations among their layers.

RESULTS:

The environmental standard induced laminar changes in different models of all layers, identifying increases and decreases in the number of astrocytes (PF groups, Stratum lacunosum-moleculare; and MF, in all layers). In the enriched environment, significant changes were observed only in the pyramidal layer (between the ages of 6 and 12 months and of 6 to 18 months, with reduction in number of astrocytes).

CONCLUSION:

The differences found depend on diet, age and aging, suggesting that astrocytosis in young adult mice would be related to neuroprotective mechanisms and that masticatory deprivation at that age would influence this action negatively. In addition, astrocytes during aging would be involved in pro-inflammatory processes if associated with a condition in chewing alteration and environmental enrichment would provide neuroprotection to the malefic effects of aging and masticatory deprivation.

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