Dissertação
Avaliação da expressão do receptor do tipo 2 de Neuromedina U no hipotálamo em modelo murino de ciclagem de peso e compulsão alimentar
Fecha
2022-03-24Autor
Alessandra Rocha Job
Institución
Resumen
Weight cycling is a term used for the profile of weight loss and gain resulting from
restrictive diets that can harm health in addition to the development of eating
disorders. One of these disorders is binge eating (BED) which affects about 3.5% of
women and 2% of men. The development of TCA is multifactorial and its
neurobiology is not yet fully elucidated, however recent evidence points to the
participation of the neuropeptide Neuromedin U and its receptors. Neuromedin U
receptor type 2 (NMUR2) deficiency in the mouse hypothalamus leads to a higher
intake of hyper palatable foods. The aim of this study was to verify whether mice
submitted to different diets that can stimulate weight cycling and/or binge eating
cause changes in anxiety and compulsion-like behaviors, correlating with NMUR2
protein abundance in the hypothalamus. Adult male C57BL/6J mice were divided into
four groups and submitted to 4 different types of diet for a period of 6 weeks. Caloric
restriction consisted of offering 60% of the usual amount of commercial food and the
Oreo cookie was used as a hyper palatable food. The diet binge 1 (CP1) group
received the Oreo along with the standard chow, alternating with weeks of calorie
restriction. The diet binge 2 (CP2) group received standard chow alternating with
weeks of calorie restriction. The binge eating (CA) group received standard chow
along with Oreo weekly. The control group (CTRL) received standard diet only. The
study evaluated whether the diets altered food consumption, induced weight cycling
and/or binge eating, in addition to the development of anxious/compulsive behavior
by the elevated plus maze (LCE) and "marble burying" tests. The results indicate that
CP1 and CP2 presented weight cycling during the cycles and that the calories
ingested at the end of the treatment were statistically superior to the other groups.
Feed efficiency was calculated and it was observed that weight cycling decreases
this efficiency, the opposite being observed when there was no cycling. The groups
showed changes in the time spent in the open arms in the LCE test, but the CP1
group remained statistically longer in the closed arms. The marble burying test
showed that CP1 and CA buried statistically more marbles in the first 10 minutes of
the test when compared to the other groups. The protein levels of NMUR2 in the
hypothalamus did not show statistical differences between the groups. The study,
therefore, suggests that weight cycling is associated with increased caloric intake,
decreased feed efficiency, anxious-like behavior pattern, but without significant
changes in NMUR2 protein abundance in the hypothalamus.