Effects of long-term sucrose overfeeding on rat brown adipose tissue: a structural and immunohistochemical study

Abstract

The aim of this study was to determine the effects of long-term sucrose overfeeding on functional capacity and ultrastructural characteristics of the rat brown adipose tissue (BAT). For the study, 16 male Wistar rats, chow-fed and kept under standard laboratory conditions, were divided into 2 equal groups. The rats from a control group drank tap water, whereas those from a sucrose overfed group were allowed to drink 10% sucrose solution for 21 days. Structural changes of BAT were analysed at the level of light and electron microscopy on routinely prepared tissue sections or using immunohistochemical staining, in combination with stereological methods. Obtained results have shown that the significantly increased energy intake in sucrose overfed rats did not result in a higher gain of body mass compared with controls. The light microscopy analysis revealed that the BAT acquired the appearance of a thermogenically active tissue, with intensified vascularisation, reduced size of brown adipocytes and increased multilocularity. At the ultrastructural level, mitochondria of brown adipocytes became more abundant, enlarged and contained more cristae in comparison to control animals. The immunoexpression of uncoupling protein 1 (UCP1) and noradrenaline, as markers of BAT thermogenic status, was increased, whereas the pattern of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) was slightly modified. Taken together, the results of this investigation indicated that BAT possesses the ability to increase thermogenic capacity/activity in response to high energy intake and to prevent body mass gain. These findings are particularly relevant in view of recent reports on the existence of functional BAT in adult humans and its potential use to combat obesity.

Jicama (Pachyrhizus erosus) fiber prevents excessive blood glucose and body weight increase without affecting food intake in mice fed with high-sugar diet

“…BAT plays a pivotal role in energy expenditure through the thermogenesis process [36]. It has been reported that HSD could reduce BAT mass particularly the interscapular BAT in rats [12]. Similarly, we also revealed that HSD reduced interscapular BAT mass.…”

Intact innervation is essential for diet-induced recruitment of brown adipose tissue

“…Feeding mice a calorie-rich obesogenic diet, especially under conditions of low thermogenic stimulus (i.e., at thermoneutrality), leads to a gradual recruitment of BAT, as indicated by increased total UCP1 levels and an increased thermogenic response to norepinephrine (3, 20, 33, 48, 61–63, 81, 85). To examine the necessity of tissue innervation for the control of the recruitment response, we denervated the interscapular brown adipose tissue depot (IBAT) of wild-type (WT) mice and fed them either chow or high-fat diet under thermoneutral conditions.…”

Pancreoprotective Effect of Jicama (Pachyrhizus erosus, Fabaceae) Fiber against High-Sugar Diet in Mice

“…Chronic intake of high concentration sucrose is considerably attributed to a marked increase of blood glucose and its subsequent pathological outcomes including pancreatic damage and apparent metabolic dysregulations [17]. It has been reported by the previous study [18] that high glucose intake could cause glucotoxicity, a condition in which pancreatic cells including β cells and insulin-targeted cells are chronically exposed to a supraphysiological glucose concentration.…”