At similar weight loss, dietary composition determines the degree of glycemic improvement in diet-induced obese C57BL/6 mice.

ABSTRACT:

Background

Achieving weight loss is the cornerstone of the treatment of the metabolic consequences of obesity, in particular of glucose intolerance.

Objective

To determine whether improvement in glucose control depends on dietary macronutrient composition of the diet at identical weight loss.

Materials and methods

Twenty-two weeks old diet-induced obese C57BL/6 mice lost weight through caloric restriction on normal chow (R-NC) or high fat diet (R-HF). Control mice were fed normal chow (LEAN) or high fat diet (OBESE) ad libitum. Body weight and composition were assessed after 8 weeks of dietary intervention. Glucose homeostasis was evaluated by intraperitoneal glucose tolerance tests (IPGTT). Epididymal white adipose (eWAT) and hepatic tissues were analyzed by immunohistochemistry and RT-qPCR.

Results

By 30 weeks of age, the body weight of the mice on R-NC (31.6±1.7g, mean±SEM) and R-HF (32.3±0.9g) was similar to LEAN mice (31.9±1.4g), while OBESE mice weighed 51.7±2.4g. Glucose tolerance in R-NC was better than in LEAN mice (69% AUC IPGTT, P 0.0168) whereas R-HF mice remained significantly less glucose tolerant (125% AUC IPGTT, P 0.0279 vs LEAN), despite identical weight loss. The eWAT pads and adipocyte size were similar in LEAN and R-NC mice, while the eWAT pad size of R-HF was 180% of R-NC (P < 0.0001) and the average adipocyte size of R-HF mice was 134% of R-NC fed mice (P 0.0285). No LEAN or R-NC mice had hepatic steatosis, in contrast to 28.6% of R-HF mice. Compared to OBESE mice, inflammatory markers were lower in eWAT and liver tissue of R-NC, but not in R-HF mice. Measures of visceral adiposity correlated well with glucose tolerance parameters.

Conclusions

In mice, caloric restriction on a normal chow diet improved glucose tolerance significantly more when identical weight loss was achieved on a high fat diet.

SUBMITTER: Vangoitsenhoven R 

PROVIDER: S-EPMC6056053 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature