The impact of small doses of LPS on NASH in high sucrose and high fat diet induced rats.

OBJECTIVE We investigated the impact of small doses of lipolysaccharide (LPS) on the development of NASH in the context of a high sucrose and high fat diet in rats. MATERIALS AND METHODS Male Wistar rats were randomly divided into groups fed a synthetic diet (n=8), a regular diet (n=8), a synthetic diet + LPS (n=8) or saline (n=8) and a regular diet + LPS (n=8) or saline (n=8). The LPS (or saline) was administered from the 6th week on (0.5 mg/kg) by subcutaneous injection every two days under the same conditions with free access to water and food. At the end of the 9th week the animals were euthanized and the liver tissue dissected for analysis. Hematoxylin and eosin (HE) and Von Gieson's (VG) staining was performed on parafin embedded sections to observe the pathological changes of the liver, the degree of fibrosis, and infiltrative lymphocytes were counted in the liver tissue. RESULTS We quantitatively measured the levels of LPS in the plasma of rats, ALT activity, and TNF-alpha. We found that the synthetic diet + LPS group showed severe steatosis, and was associated with bridging necrosis and mild fibrosis when compared to the group fed a Synthetic diet + saline. In addition, the amount of infiltrative lymphocytes and the level of plasma ALT and TNF-alpha in the synthetic diet + LPS group were significantly increased. The difference observed were statistically significant (p < 0.05). CONCLUSIONS Small doses of LPS promote the development of NASH induced by a high sucrose and high fat.