Maternal Roux-en-Y gastric bypass surgery reduces lipid deposition and increases UCP1 expression in the brown adipose tissue of male offspring

Abstract

Maternal obesity induced by cafeteria diet (CAF) predisposes offspring to obesity and metabolic diseases, events that could be avoided by maternal bariatric surgery (BS). Herein we evaluated whether maternal BS is able to modulate brown adipose tissue (BAT) morphology and function in adult male rats born from obese female rats submitted to Roux-en-Y gastric bypass (RYGB). For this, adult male rat offspring were obtained from female rats that consumed standard diet (CTL), or CAF diet, and were submitted to simulated operation or RYGB. Analysis of offspring showed that, at 120 days of life, the maternal CAF diet induced adiposity and decreased the expression of mitochondrial Complex I (CI) and Complex III (CIII) in the BAT, resulting in higher accumulation of lipids than in BAT from offspring of CTL dams. Moreover, maternal RYGB increased UCP1 expression and prevented excessive deposition of lipids in the BAT of adult male offspring rats. However, maternal RYGB failed to reverse the effects of maternal diet on CI and CIII expression. Thus, maternal CAF promotes higher lipid deposition in the BAT of offspring, contributing to elevated adiposity. Maternal RYGB prevented obesity in offspring, probably by increasing the expression of UCP1.

Figure 1

Biometric and serum biochemical parameters in maternal groups submitted, or not, to RYGB. CTL, female rats fed standard diet (n = 5–11 animals); CAF-SHAM, female rats fed on CAF diet and submitted to sham operation (n = 5–12 animals); CAF-RYGB, female rats fed on CAF diet and submitted to RYGB (n = 5–22 animals). Maternal biometric and biochemical parameters were analysed: Evolution of body weight with the CAF diet, before and after RYGB or SHAM operation (a), body weight before surgery (b), body weight after surgery (c), body weight area under curve (d), Fat pads (e), glycaemia (f), insulin (g), HOMA-IR (h). Different letters indicate statistical differences by one-way ANOVA and Bonferroni post-test (p < 0.05). The data are mean ± SEM. *p < 0.05 (Student’s t test). #p < 0.05 (CAF-RYGB vs CAF-SHAM).

Figure 2

Metabolic parameters in offspring from dams submitted, or not, to RYGB. CTL_F1, offspring of rats fed standard diet (n = 36 animals); CAF-SHAM_F1, offspring of rats fed on CAF diet and submitted to sham operation (n = 28 animals); CAF-RYGB_F1, offspring of rats fed on CAF diet and submitted to RYGB (n = 14 animals). Weight gain (a) and food intake (c) were measured weekly. Metabolic parameters were analysed and presented, by AUC, the weight gain (b), total food consumption (d), feeding efficiency (e), total energy intake (f), energy intake per gram of body weight (g) and total energy expenditure (h). Different letters indicate statistical differences by one-way ANOVA and Bonferroni post-test (p < 0.05). The data are mean ± SEM. *p < 0.05.

Figure 3

Effect of maternal obesity and RYGB on BAT weight and the nucleus number and adipocyte size in the BAT of male adult offspring rats. CTL_F1, offspring of rats fed standard diet; CAF-SHAM_F1, offspring of rats fed on CAF diet and submitted to sham operation; CAF-RYGB_F1, offspring of rats fed on CAF diet and submitted to RYGB (n = 6 animals/group). Weight of BAT (a), nucleus number (b) and adipocyte size (c) were analysed by light microscopy. Different letters indicate statistical differences by one-way ANOVA and Bonferroni post-test (p < 0.05). Representative photomicrograph (insert) of BAT (40x), stained with H&E are showed in the figures (d) (CTL_F1), (e) (CAF-SHAM _F1) and (f) (CAF-RYGB_F1). Arrows indicate nuclei and boxes indicate adipocyte area. The data are mean ± SEM.

Figure 4

Effect of maternal obesity and RYGB on the distribution of fat, nuclei and BVM in the BAT of male adult offspring rats. CTL_F1, offspring of rats fed standard diet; CAF-SHAM_F1, offspring of rats fed on CAF diet and submitted to sham operation; CAF-RYGB_F1, offspring of rats fed on CAF diet and submitted to RYGB (n = 6 animals/group). The percentages of the total area occupied by lipids (a), BVM (b) and nuclei (c) were analysed. Different letters indicate statistical differences by one-way ANOVA and Bonferroni post-test (p < 0.05). Representative photomicrograph (insert) of BAT (40x), stained with H&E are showed in the figures (d) (CTL_F1), (e) (CAF-SHAM_F1) and (f) (CAF-RYGB_F1). The images were processed with Image J Program as explained in methods section. Groups are in rows. CTL_F1, CAF-SHAM_F1 and CAF-RYGB_F1. In columns original image (d–f), adipocytes in yellow (g–i), BVM in blue (j–l) and Nuclei in black (m–o). Fully treated image (p–r). The data are means ± SEM.

Figure 5

Effect of maternal obesity and RYGB on UCP1 expression in BAT of adult male offspring. CTL_F1, offspring of rats fed standard diet; CAF-SHAM_F1, offspring of rats fed on CAF diet and submitted to sham operation; CAF-RYGB_F1, offspring of rats fed on CAF diet and submitted to RYGB (n = 4 animals/group). UCP1 expression (a), was analysed by Western Blot, normalized by α tubulin protein expression (b), and correlated UCP1 expression with adipocyte size (c). Data are represented as means ± SEM. Different letters indicate statistical differences by one-way ANOVA and Bonferroni post-test (p < 0.05). UCP1, uncoupling protein 1. Correlation was analysed using nonparametric Spearman’s test. p values less than 0.05 were considered significant. Uncropped images in supplementary figure.

Figure 6

Effects of maternal obesity and RYGB on the expression of complexes (CI-CV) of the electron transport chain in adult offspring. CTL_F1, offspring of rats fed standard diet; CAF-SHAM_F1, offspring of rats fed on CAF diet and submitted to sham operation; CAF-RYGB_F1, offspring of rats fed on CAF diet and submitted to RYGB (n = 4 animals/group). ETC protein expression (a) was analysed by Western Blot and normalized by GADPH protein expression (b). Different letters indicate statistical differences by one-way ANOVA and Bonferroni post-test (p < 0.05). ETC, electron transport chain. GAPDH, Glyceraldehyde 3-phosphate dehydrogenase. CI, CII, CIII, CIV, CV, complex I–V. Data are represented as means ± SEM. Uncropped images in supplementary figure.

Figure 7

Design of experimental groups. Control Group (CTL), dams received standard diet throughout life (n = 13); Cafeteria Group (CAF), dams received cafeteria diet throughout life (n = 34); Cafeteria Group SHAM (CAF-SHAM; n = 14), dams received cafeteria diet throughout life and were submitted to sham operation; Cafeteria submitted to RYGB (CAF-RYGB; n = 20), dams received cafeteria diet throughout life and were submitted to roux y gastric bypass. Offspring (F1): CTL_F1, offspring of rats fed on standard diet; CAF-SHAM_F1, offspring of rats fed on CAF diet and submitted to sham operation; CAF-RYGB_F1, offspring of rats fed on CAF diet and submitted to RYGB (n = 6–12 rats/groups). ♀ Female; ♂ male.