Repeated Starvation Leads Fat Accumulation in Caenorhabditis elegans

Abstract

Our aim is to define the effect of repeated-starvation on organism using nematode Caenorhabditis elegans. Adult worms were exposed to two cycles of 6 hr starvation-18 hr feeding protocol, and fat content in worms was analyzed by Nile Red staining and biochemical quantification. The expression of genes involved in fat synthesis (pod-2, fasn-1, mboa-2, sbp-1) and fat degradation (hosl-1, lipl-4, cpt-1, cpt-2, B03003.3, F53a2.7) was also analyzed by quantitative RT-PCR. Both Nile Red staining and biochemical quantification showed that fat content in worms that experienced repeated-starvation increased. There was no obvious change in the expression of genes involved in fat synthesis, but those of genes involved in fat degradation tended to decrease, which is consistent with the increment of fat in worms experienced repeated-starvation. The lifespan, fecundity and mobility of worms that experienced repeated-starvation did not show remarkable differences compared to those of the fed worms. However, the pharyngeal pumping increased upon experiencing starvation, indicating amount of food intake increased by starvation. Our results indicate that repeated-starvation caused metabolic and nutritional effect in worms. It is often mentioned that repeating weight loss leads to weight regain, sometimes referred as “weight rebound”, and our data may also provide a molecular basis of weight regain.