Mice can get Obese

 By: Vianey Trevino

Data collected at the end of 16 weeks after inoculation of Gnotobiotic mice with E.cloacae B29, becoming obese and insulin resistant with increased endotoxin load and provoked systemic inflammation under HFD feeding.  (a) Body Weight (b) Mass of epididymal, mesenteric ,subcutaneous inguinal and retroperitoneal fat pad. (c) abdominal photographs (d) oral glucose tolerance test and the areas under the curve for the plasma glucose (e) serum 2 h post load insuline (f) enzyme-linked immunosorbent assay analysis of serum LPS-binding protein (g) serum amyloid a and (h) adiponectin corrected for body weight

Lipopolysaccharide (LPS) a major component of the outer membrane of gram-negative bacteria. LPS activates cell of the innate immune system, as well as creates an absorbent barrier at the cell surface and is a main contributor to the innate resistance that gram-negative bacteria displays against antimicrobial. Their research is about a (LPS) endotoxin purified from Escheria coli that once induced in a mice it becomes obese and insulin resistance. They began their research by finding out that the pathogen made up 35% of the gut bacteria in obese volunteer. Then they had the volunteer on a 23week diet composed of whole Chinese medicinal foods and prebiotic, after 9 weeks the volunteer gut reduced 1.8%. After they obtained a fecal sample and identified it as Enterobactercloacae. Due to the previous studies showing that germ free mice are resistance to HFD-induced obesity, they inoculated 10^10 cells of B29 everyday for the first week into 6-10 week old germ-free mice under normal chow diet. This is important because germ-free mice have been used for obesity studies, as well as can contribute to human obesity.

Reference:

Fei, N., Zhao, L. An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice. ISME J 7, 880–884 (2013). https://doi.org/10.1038/ismej.2012.153