Sensitization of Kupffer cells (KCs) to lipopolysaccharide (LPS) and overproduction of tumor necrosis factor (TNF) α are critical for progression of alcoholic liver injury. Thalidomide has been shown to suppress TNF-α production from macrophages. Accordingly, the purpose of this study was to determine whether thalidomide could prevent alcohol-induced liver injury.

Rats were given ethanol (5 g/kg body wt) and thalidomide (5 mg/kg) once every 24 hours intragastrically. To assess the sensitization of Kupffer cells, LPS (5 mg/kg intravenously) was administered and liver histology was evaluated 24 hours later. KCs were isolated after 4 weeks of ethanol treatment and intracellular Ca²⁺ ([Ca²⁺]_i) was measured using fura-2, whereas TNF-α was evaluated by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay. CD14 was determined by Western and fluorescence staining.

Treatment with ethanol for 8 weeks caused marked steatosis, necrosis, and inflammation in the liver. These pathologic parameters were diminished markedly by treatment with thalidomide. In the 4-week ethanol group, the LPS-induced liver damage was aggravated and KCs were sensitized to LPS. Coadministration of thalidomide with ethanol prevented the KC sensitization completely. Furthermore, thalidomide abolished the LPS-induced increase in CD14 expression and [Ca²⁺]_i elevation in KCs. Gut permeability was increased about 10-fold after 4 weeks of ethanol exposure, which was not affected by thalidomide. Moreover, thalidomide reduced the LPS-induced TNF-α production by KCs by decreasing TNF-α messenger RNA.

These results collectively indicate that thalidomide prevents alcoholic liver injury through suppression of TNF-α production and abolishment of KC sensitization.