Attenuation Effects of Bulk and Nanosized ZnO on Glucose, Lipid Level, and Inflammation Profile in Obese Mice

Gut microbiota in the association between obesity and kidney function decline: a metagenomics-based study in a rat model

OBJECTIVES

Obesity can induce dysbiosis in the gut microbiota and is considered a separate risk factor for kidney function decline. Nonetheless, the precise function of intestinal microorganisms in facilitating the connection between obesity and kidney function decline remains uncertain. Hence, the objective of this study was to investigate the alterations in the gut microbiota composition that take place during obesity and their correlations with renal function utilizing a rat model.

METHODS

For 20 weeks, 25 Sprague-Dawley rats were fed either a high-fat diet (HFD) or a normal-fat normal diet (ND). Physiological indices, peripheral plasma, kidney tissue, and colon contents were collected for comparison between groups. Metagenomic analysis of intestinal flora was performed.

RESULTS

The HFD group demonstrated significantly increased levels of creatinine and urea nitrogen in the peripheral blood. Additionally, the HFD rats exhibited a significantly larger glomerular diameter compared to the ND group, accompanied by the presence of glomerulosclerosis, tubular vacuolar transformation, and other pathological changes in certain glomeruli. Metagenomics analysis revealed a notable rise in the prevalence of the Firmicutes phylum within the HFD group, primarily comprising the Rumenococcus genus. Functional analysis indicated that the gut microbiota in the HFD group primarily correlated with infectious diseases, signal transduction, and signaling molecules and interactions.

CONCLUSIONS

This study provides evidence that the consumption of a HFD induces modifications in the composition and functionality of the gut microbiome in rats, which may serve as a potential mechanism underlying the relationship between obesity and the progression of kidney function decline.

Alginate Calcium Microbeads Containing Chitosan Nanoparticles for Controlled Insulin Release

Effective delivery system for oral insulin administration is a promising way for diabetes therapy. Herein, we prepared alginate microbeads containing chitosan nanoparticles (CNP) for controlled release of insulin. CNP was developed by reaction between tripolyphosphate (TPP) and chitosan. The ratio of TPP to chitosan was optimized aiming with smaller and more unified distributed CNP. TEM and DLS analysis confirmed that CNP has size around 150 nm with low PDI value and strong surface charge. Encapsulate ability for bovine serum albumin, working as model protein, was 11.45%, and the encapsulate efficiency was 23.70%. To modify the release profile of protein suitable for oral insulin delivery, sodium alginate was applied to coat on the surface of CNP by electrostatic interaction. After that, CaCl₂ was added to reinforce the alginate coating layer. FTIR analysis confirmed the interaction of alginate with chitosan and reaction with calcium ion. After reaction with Ca²⁺ ion, size measurement revealed that CNP was incorporated into alginate microbeads with mean diameter about 3.197 μm. Alginate microbeads presented irregular shape with small particles inside as revealed by optical microscope. Meanwhile, the release test demonstrated that protein release was pH-dependent. Acidic pH value retards protein release and neutral pH value promotes protein release. At last, insulin-loaded alginate microbeads were administrated to hyperglycemia model mice and blood glucose profile was monitored afterward. Insulin-loaded microbeads significantly lowered blood glucose level compared with mice treated with alginate microbeads without insulin. It is noted that insulin-loaded alginate microbeads could lower blood glucose level in much prolonged period of 96 h, indicating that insulin was released in controlled manner.

High fat diet induced obesity model using four strainsof mice: Kunming, C57BL/6, BALB/c and ICR

High fat diet (HFD) treated mouse is widely used as experimental animal model for hyperlipidemia and hyperglycemia study. Many factors contribute to establish animal model that meant to simulate high fat and glucose diet induced phenotypes. In the present study, four strains of experiment mouse treated by HFD were used to explore the impact of mouse strain on lipid profile, glucose level, and major inflammation cytokines. HFD fed Kunming and ICR mouse gained significantly higher body weight than control which was not shown by C57BL/6 and BALB/c mouse. All four strains fed by HFD has heavier liver and adipose tissue than control ones. Obvious fat droplets and enlarged adipose cells were observed in obese mouse of four strains. Additionally, obese mouse showed typical response to glucose and insulin load in OGTT and ITT. Serum TC, LDL-c, and TC/HDL-c ratio, but not TG, increased in all four strains. Major inflammatory cytokines and insulin level showed little changes in obese mouse as well (P<0.05) The present study could provide basic information for diet induced obesity developed by four commonly used experimental mouse strains.