Leflunomide attenuates hepatocyte injury by inhibiting Kupffer cells

Abstract

AIM: To investigate the importance of direct contact between Kupffer cells (KCs) and hepatocytes (HCs) during hepatic inflammatory responses, and the effect of leflunomide’s active metabolite, A₇₇₁₇₂₆, on cytokines in KCs, HCs and KC cocultures (DC cocultures).

METHODS: KCs and HCs in liver were isolated by digestion with pronase and collagenase. Lipopolysaccharide (LPS) -induced inflammatory response in monocultures of rat HCs and KCs was compared with that in DC cocultures. Tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) concentrations in different culture supernatants were measured with ELISA. TNF-α mRNA in KCs of inflammatory liver injury was analyzed with reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS: DC cocultures strongly exhibited the production of TNF-α and IL-1 compared with other cultures, and these cytokines were mainly produced by KCs, especially by activated KCs. Time course studies revealed an increased production of TNF-α preceding the IL-1 production, suggesting that increased TNF-α levels could be involved in the increase of IL-1 production. Leflunomide’s active metabolite, A₇₇₁₇₂₆, had significantly inhibitory effect on TNF-α and IL-1 at protein and transcription levels, and the reduced production of IL-1 by A₇₇₁₇₂₆ was associated with the inhibitory action of A₇₇₁₇₂₆ on TNF-α.

CONCLUSION: Leflunomide can inhibit hepatocyte damage by inhibiting proinflammatory cytokine release from KCs.

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