Aim: 

To know the modifications that fasting induces on the cultures of adipose cells.

Methods: 

Cells were obtained from epididymal fat pad. Control rats were fed ad libitum, while fasted rats were fed 60% of normal food intake. Primary cultures were performed when fasted rats had lost 25-30% of their initial weight. The first, second day, and every 3 days, cells were photographed to count and follow the progress of the cells. Bisbenzimide was used to count the number of cell nucleus and SOX-2 antibodies to identify progenitor cells.

Results: 

In the first day, 28,2% of total cells in the cultures from fasted rats were round multivacuolated cells and only 1,3% in the cultures from control rats. The multivacuolated cells showed fat drops as stained with red oil, and some of them were SOX-2 positives. At the end of the first week, the percentage of multivacuolated cells in cultures of fasted rats was 48% and 0.45% in the control rats. Many of mature cells from fasted rats could derivate from the multivacuolated cells, as depicted from some images of cell division. After two weeks, the differences in the number of mature cells were reduced between both types of cultures (36,8% fasted rats and 12,3 fed rats), suggesting that fat cells from control rats should come only from preadipocytes resident in the tissue.

Conclusions: 

Food restriction transforms some existing cells of adipose tissue in round multivacuolated cells with capacity of proliferation and differentiation. This may explain the quickly regaining of weight after a fasted period.