RESUMO
Aim: To observe the effect of cold exposure on browning of white adipose tissues in mice fed with high fat diet. Methods: Male 8-week-old C57BL/6J mice were randomly divided into HFD + 5 °C group and HFD + RT group, after 8 weeks of high-fat diet. Male 8-week-old C57BL/6J mice were randomly divided into normal + 5 °C group and normal + RT group, after 8 weeks of normal diet. Each group of mice were intervened for 2 h at different temperatures in the same time period for 8 weeks. Parameters, including body weight, food intake, inguinal white adipose tissue (iWAT) mass, brown adipose tissue (BAT) mass, blood glucose, blood lipids, leptin, adiponectin, adipose tissue pathology and in situ expression of uncoupling protein 1(UCP1) and prohibitin protein (PHB) in iWAT and BAT. Results: Compared with HFD + RT group, cold exposure not only significantly reduced body weight, blood glucose, iWAT weight/body weight ratio, TC, TG, LDL-C and leptin, but also increased food intake and BAT weight in high-fat diet mice. HE staining showed that iWAT and BAT cells became smaller and had multiple compartments. The iWAT had a browning trend. Immunohistochemistry showed that UCP1 and PHB protein in iWAT and BAT significantly increased. Conclusions: Cold exposure can counteract the weight gain caused by a high-fat diet, which may be related to the activation of brown adipose tissue and the induction of browning of white adipose tissues, increasing heat production and reducing white fat accumulation.
RESUMO
Objective To study the effects of berberine (BBR) on the gene mRNA expression of fat-specific protein 27 (FSP27) and PR domain containing 16 (PRDM16) signal pathway in visceral white adipose tissues (VWAT) from type 2 dia? betic (T2DM) Chinese hamsters, and explore the related mechanisms. Methods The obese insulin-resistant (OIR) hamster model was induced by high-fat diet, and T2DM hamster model was created by OIR hamster model injected with low-dose streptozotocin. The control group was fed with standard laboratory chow. After the induction, the hamsters were randomly di?vided into control, OIR, obese T2DM and BBR-treated T2DM groups. After nine-week BBR treatment, real-time quantita?tive PCR was used to measure the gene mRNA expression changes of VWAT FSP27 and PRDM16 signal pathway and their target genes from different groups. Results Compared with control group, the gene mRNA expressions of PRDM16, CtBP-1, CtBP-2, C/EBPβ, PPARγ, PGC1α, PGC-1β and brown adipose tissue-specific genes such as UCP-1, Cidea, Elovl3, PPARα, and Acox, Cpt1 and Acadm were decreased and that of FSP27 and white adipose tissue-specific genes including Resistin, MEST and Serpina3k were increased in VWAT in OIR and obese T2DM groups. BBR treatment down-regulated FSP27 expression, enhanced PRDM16 signal pathway, and induced the gene mRNA expression of brown adipose tissue-spe?cific genes in VWAT of obese T2DM group to develop browning gene phenotype of VWAT, and then improved fat-induced insulin resistance. Conclusion The decreased FSP27 expression and increased PRDM16 expression are involved in the molecular mechanisms of browning of visceral white adipose tissues induced by BBR, and which contributes to improve ab?normal lipids metabolism and fat-induced insulin resistance in VWAT by enhancing consumption of energy as heat to re?store VWAT function.
RESUMO
To study the effects of berberine on the gene mRNA expressions of BMP4 transcriptional pathways and brown/white adipose tissue conversion transcriptional pathways in visceral white adipose tissues(VWAT) in type 2 diabetic hamsters and explore the relevant mechanisms. The obese insulin-resistant hamster model were induced by using high-fat diet, and then the type 2 diabetic hamster model was created through injection with low-dose streptozotocin in the obese insulin-resistant hamster model. After the modeling, the hamsters were randomly divided into normal control, obese insulin-resistant, type 2 diabetic and berberine-treated diabetic groups. After the nine-week treatment, real-time quantitative PCR was used to measure the changes in gene mRNA expressions of VWAT BMP4 transcriptional pathways, brown/white adipose tissue conversion transcriptional pathways and their target genes in different groups. The results showed that the gene mRNA expressions of BMP4, BMPRⅡ, BMPRlA, Smad1, Smad5, Smad8, p38/MAPK, ATF2, PRDM16, C/EBPβ, PGC1α, PPARγ and brown adipose tissue-specific genes was decreased and that of Smad6, Smurf1 and white adipose tissue-specific genes was increased in VWAT of model hamsters. Treatment with berberine regulated BMP4 transcriptional pathways and brown adipose tissue transcriptional pathways and induced the gene mRNA expression of brown adipose tissue-specific genes in VWAT to develop browning gene phenotype of white adipose tissues, and then improved fat-induced insulin resistance. These findings indicated that BMP4 transcriptional pathways involved in the formation of fat-induced visceral white adipose tissues insulin resistance (FIVWATIR) and the browning molecular mechanism of white adipose tissues induced by berberine.