129] HEMEOXYGENASE-1 EXPRESSION BY KUPFFER CELLS IS REQUIRED FOR CELLULAR SURVIVAL OF HEPATIC ISCHAEMIA REPERFUSION INJURY

Abstract

Background and Aims: Tschaemia reperfusion injury (TRT) arises from interruption of the hepatic blood supply. Hemeoxygenase-l (hmoxI ) catalyzes degradation of heme into biliverdin, Fe2+ and carbon monoxide. It has been shown to protect animals and cells from 1R1. Hmox-1 is localized within Kupffer cells (KCs). GdC13 is used to inhibit macrophage phagocytosis, and Liposomal Clodronate (LC) is used to selectively ablate macrophages. Methods: Littermate hmox-1 +/+, +/-, -/mice and wildtype C57iB6 animals were treated with GdC13, liposomal clodronate (LC) or vehicle. Under isoflurane anaesthesia, animals underwent 40 or 50 minutes’ hepatic left lobar ischaemia followed by recovery and kill at 24 hours. Blood was analysed for ALT: results are presented as meanfSEM. Western blots of liver lysates were performed for hmoxI . Tmmunohistochemistry was performed for hmox-1 and macrophage markers CD68, CD1 lb, and F4180. Results: Hmox-I -/but not hmox+/mice are susceptible to hepatic TRT and exhibit abnormal KC phenotype. Following 40’ hepatic ischaemia, mean ALT was 9515&1437 (hmox-1 -/-), 403f99 (hmox+/-), 214f28 (hmox-1 +/+) (p iO.OOO1). KCs in hmox+/+ and +/animals were CDllb+ CD68+, F4/80+ whereas KCs in hmox-1-/animals were CDI I b+, CD68+, F4/80with aberrant morphology. GDCWreated mice are protected from hepatic IRI and have hmox-l upregulation. Following 50’ hepatic ischaemia, mean ALT was I929+404 (GdCKtreated mice) and 4467+532 (untreated) (p = 0.007). Hmox-I was upregulated in the GdC13 group. KCs were CDI 1 b+, CD68+, F4/80+ and of normal number. KC-ablated mice have downregulated hmox-1 and are susceptible to hepatic 1R1. Following 50’ hepatic ischaemia, mean ALT was 19,300f3523 (LC treated mice) and 4467&532 (untreated mice, as above) (p 0.0001). Western blotting demonstrated complete loss of hmox-1 expression in the LC treated group. KCs were entirely ablated. Discussion: Hmox-1 is required for hepatic survival from ischaemia reperfusion insults Furthermore, cellular localization of hmox-1 with KCs is cntical. hmox-l is required for normal differentiation of KCs and conversely, KCs are required for normal hmox-I stress responses 11301 ADENOVIRAL GENE DELIVERY OF INTERLEUKIN-I0 REDUCES HEPATIC ISCHEMIA-REPERFUSION INJURY IN RATS THRU INHIBITION OF KUPFFER CELL ACTIVATION