Protective effect of pioglitazone against endotoxin-induced liver injury through prevention of Kupffer cell...

Activation of Kupffer cells by lipopolysaccharide (LPS) plays a pivotal role in the onset of pathophysiological events that occur during endotoxemia and intracellular calcium ([Ca]i) is involved in LPS-stimulated cytokine production. TNF-alpha is produced exclusively by the monocyte-macrophage lineage, including Kupffer cells, and pioglitazone has been shown to reduce TNF-alpha production from macrophages. On the other hand, there is increasing evidence that TNF-alpha plays a major role in the initiation and/or progression of multiple organ failure syndrome. Therefore, the purpose of this work was to determine whether pioglitazone could prevent LPS-induced liver injury

Rats were given a single oral dose of pioglitazone (500 microg/kg). To assess the sensitization of Kupffer cells, LPS (5 mg/kg) was administered IV and transaminases were evaluated 24 hr later. Kupffer cells were isolated 2 hr after pioglitazone treatment. After addition of LPS, [Ca]i was measured using a microspectrofluorometer with the fluorescent indicator, fura-2, and TNF-alpha was measured by ELISA RESULTS: LPS increased transaminases dramatically and elevation of serum transaminases were diminished markedly by pioglitazone. In isolated Kupffer cells, the LPS-induced increase in [Ca]i and TNF-alpha production were suppressed by treated with pioglitazone

Therefore, it is concluded that pioglitazone prevents LPS induced liver injury via a mechanism dependent on suppression of TNF-alpha production from Kupffer cells.