Effects of high fat diet, ovariectomy, and physical activity on leptin receptor expression in rat brain and white fat tissue

Abstract

AimTo evaluate in a rat animal model whether ovariectomy, high fat diet (HFD), and physical activity in the form of running affect leptin receptor (Ob-R) distribution in the brain and white fat tissue compared to sham (Sh) surgery, standard diet (StD), and sedentary conditions.MethodsThe study included 48 female laboratory Wistar rats (4 weeks old). Following eight weeks of feeding with standard or HFD, rats were subjected to either OVX or Sh surgery. After surgery, all animals continued StD or HFD for the next 10 weeks. During these 10 weeks, ovariectomy and Sh groups were subjected to physical activity or sedentary conditions. Free-floating immunohistochemistry and Western blot methods were carried out to detect Ob-R in the brain and adipose tissue.ResultsStD-ovariectomy-sedentary group had a greater number of Ob-R positive neurons in lateral hypothalamic nuclei than StD-Sh-sedentary group. There was no difference in Ob-R positive neurons in arcuatus nuclei between all groups. Ob-R distribution in the barrel cortex was higher in HFD group than in StD group. Ob-R presence in perirenal and subcutaneous fat was decreased in StD-ovariectomy group.ConclusionHFD and ovariectomy increased Ob-R distribution in lateral hypothalamic nuclei, but there was no effect on arcuatus nuclei. Our results are first to suggest that HFD, ovariectomy, and physical activity affect Ob-R distribution in the barrel cortex, which might be correlated with the role of Ob-R in election of food in rats.

High-fat diet intake induces depressive-like behavior in ovariectomized rats

“…Altogether, the results indicated that the consumption of this 45%-lard diet for 12 weeks had mild effects, perhaps due to the caloric and lipidic density of the diet as well as to the period of diet exposure. In agreement with this suggestion, other authors reported that the intake of a 45% lard-rich diet for 8 weeks by female rats failed to increase body fat percentage 35 , while a 62%-lard diet for 50 weeks doubled the body weight gain of female rats 36 . In male mice, the intake of a 60%-lard diet 16 weeks induced pronounced changes in body adiposity, glucose homeostasis, and leptinemia 37 .…”

Obesity and diabetes: the link between adipose tissue dysfunction and glucose homeostasis

“…A study conducted by Blažetić et al ( 69 ) using an animal model revealed increased distribution of leptin receptors (Ob-R) in the lateral hypothalamic nucleus, but without effect on the arcuate nucleus resulting from a fat-rich diet. This way, in obesity, despite the high concentration of circulating leptin and possible increase in the number of receptors in the brain, leptin does not induce the expected response of decreased intake and increased energy expenditure.…”

Effects of exercise on brain functions in diabetic animal models

“…They have excessive WAT in the body and it secretes leptin in the blood; however, the appetite center does not recognize leptin and shows resistance to leptin. Therefore, leptin administration to obese rats and humans has elicited small effects on fat mass and appetite due to leptin resistance [2,53,148] . Likewise, many neuropeptides located in hypothalamic nuclei transmit related anorexigenic or orexigenic signals [104,146] .…”

“…Hence, uncontrolled chronic obese condition can be a critical factor in the development of T2DM, and it also acts as an agent that affects normal brain functions. Recently many studies have shown the positive effects of regular physical activity on improving complications caused by DM, and hence regular physical activity intervention is regarded as a promising adjuvant therapy [7,37,[51][52][53][54][55][56][57][58][59][60][61][62] . Exercise can affect various physical environments and has decisive effects on improving brain functions for a better quality of life [7,[59][60][61][63][64][65][66][67][68][69][70][71][72] .…”