Identification of compounds from high-fat and extra virgin olive oil-supplemented diets in whole mouse liver extracts and isolated mitochondria using mass spectrometry

Nonalcoholic steatohepatitis (NASH) is a fatty liver disorder that could be improved with extra virgin olive oil (EVOO) supplementation in diet. We propose the monitoring, in whole mouse liver extracts and in isolated mitochondria, of the absorption of compounds from three different diets: standard (CT), high-fat (HFD) and high-fat supplemented with EVOO (HFSO). Male mice were submitted to one of the following three diets: CT or HFD for 16 weeks or HFD for 8 weeks followed by additional 8 weeks with HFSO. Following this period, liver was extracted for histological evaluation, mitochondria isolation and mass spectrometry analyses. Diets, liver extracts and Percoll-purified mitochondria were analyzed using ESI-MS and the lipidomics approach. Morphological, histological and spectrometric results indicated a decrease in NASH severity with EVOO supplementation in comparison with animals maintained with HFD. Spectrometric data also demonstrated that some compounds presented on the diets are absorbed by the mitochondria. EVOO was shown to be a potential therapeutic alternative in food for NASH. Our results are in accordance with the proposition that the major factor that influences different responses to diets is their composition - and not only calories - especially when it comes to studies on obesity.

Effects of different intensities of physical exercise on insulin sensitivity and protein kinase B/Akt activity in skeletal muscle of obese mice

Objective:

To investigate the effects of different intensities of acute exercise on insulin sensitivity and protein kinase B/Akt activity in skeletal muscle of obese mice.

Methods:

Swiss mice were randomly divided into four groups, and fed either a standard diet (control group) or high fat diet (obese sedentary group and obese exercise group 1 and 2) for 12 weeks. Two different exercise protocols were used: swimming for 1 hour with or without an overload of 5% body weight. The insulin tolerance test was performed to estimate whole-body sensitivity. Western blot technique was used to determine protein levels of protein kinase B/Akt and phosphorylation by protein Kinase B/Akt in mice skeletal muscle.

Results:

A single bout of exercise inhibited the high fat diet-induced insulin resistance. There was increase in phosphorylation by protein kinase B/Akt serine, improve in insulin signaling and reduce of fasting glucose in mice that swam for 1 hour without overload and mice that swan for 1 hour with overload of 5%. However, no significant differences were seen between exercised groups.

Conclusion:

Regardless of intensity, aerobic exercise was able to improve insulin sensitivity and phosphorylation by protein kinase B/Ak, and proved to be a good form of treatment and prevention of type 2 diabetes.

Magnesium-deficient high-fat diet: effects on adiposity, lipid profile and insulin sensitivity in growing rats

BACKGROUND & AIMS

To determine if magnesium deficiency aggravates the effects of a high-fat diet in growing rats in terms of obesity, lipid profile and insulin resistance.

METHODS

The study population comprised 48 newly weaned male Wistar Hannover rats distributed into four groups according to diet, namely, control group (CT; n = 8), control diet provided ad libitum; pair-feeding control group (PF; n = 16), control diet but in the same controlled amount as animals that received high-fat diets; high-fat diet group (HF; n = 12), and magnesium-deficient high-fat diet group (HFMg(-); n = 12). The parameters investigated were adiposity index, lipid profile, magnesium status, insulin sensitivity and the phosphorylation of proteins involved in the insulin-signaling pathway, i.e. insulin receptor β-subunit, insulin receptor substrate 1 and protein kinase B.

RESULTS

The HF and HFMg(-) groups were similar regarding gain in body mass, adiposity index and lipid profile, but were significantly different from the PF group. The HFMg(-) group exhibited alterations in magnesium homeostasis as revealed by the reduction in urinary and bone concentrations of the mineral. No inter-group differences were observed regarding glucose homeostasis. Protein phosphorylation in the insulin-signaling pathway was significantly reduced in the high-fat groups compared with the control groups, demonstrating that the intake of fat-rich diets increased insulin resistance, a syndrome that was aggravated by magnesium deficiency.

CONCLUSIONS

Under the experimental conditions tested, the intake of a magnesium-deficient high-fat diet led to alterations in the insulin-signaling pathway and, consequently, increased insulin resistance.

Comparação do processo de reparo ósseo em tíbias de ratas normais e osteopênicas

O objetivo foi comparar a consolidação óssea em tíbias de ratas normais e osteopênicas. 49 ratas albinas fêmeas, linhagem Wistar, peso médio de 160 (± 20g) e 100 dias foram distribuídas em 2 grupos: Ooforectomizado (OOF) e Pseudo-ooforectomizado (Grupo controle - SHAM). 30 dias após a ooforectomia e/ou cirurgia simulada, todas foram submetidas à produção de lesão óssea cortical. Foram sacrificadas na 2ª, 4ª, 6ª e 8ª semanas. Os osteoblastos foram contados. O peso aumentou progressivamente, porém as OOF apresentaram maior peso (p<0,05) quando comparadas as SHAM, à época da segunda cirurgia. 15 dias pós-lesão óssea, as OOF apresentaram maior número de osteoblastos (p<0,05) quando comparados as SHAM. 30 dias pós-lesão óssea houve diminuição no número de osteoblastos, porém os valores foram equivalentes entre os dois grupos OOF e SHAM. 45 dias pós-lesão, apesar da diminuição constante de osteoblastos, o grupo OOF permaneceu elevado quando comparado ao grupo controle (p<0,05). Aos 60 dias o grupo SHAM apresentou menos osteoblastos, sugerindo processo avançado de reparo ósseo. Os animais osteopênicos apresentaram resposta inicial acelerada à lesão óssea, possibilitando a equivalência entre os grupos 30 dias pós-lesão. Mas, após este período apresentaram retardo na mineralização do osteóide, sugerindo atraso tardio no processo de reparo ósseo.