Hemeoxygenase 1 inhibition induces a loss of antioxidant protection in rats with bile duct ligation

TAURIZANO, DENISE; MARTIN, PAMELA; RAZORI, MARIA VALERIA; MASSA, ESTEFANIA; PISANI, GERARDO B; ARRIAGA, SANDRA MM; SANCHEZ POZZI, ENRIQUE J.; ROMA, MARCELO GABRIEL; BASIGLIO, CECILIA L.

Rosario

Congreso; Reunión Anual de la SAFIS; 2019

Sociedad Argentina de Fisiología

We had demonstrated that hemeoxygenase 1 (HO1) induction, and consequently elevated bilirubin (BR), protects the liver from oxidative stress-inducedcholestatic injury in vivo. To corroborate this protective role of BR, we evaluated the effect of HO1 inhibition on endogenous BR levels and BR antioxidant capacity in animals subjected to a cholestatic insult. Wistar rats were subjected to bile duct ligation (BDL, n=6) or sham surgery(Sh, n=5). HO1 was inhibited by Zn(II) protoporphyrin IX(PP, 30 mg/Kg b.w., i.p.) administered 24h before BDL(PP+BDL, n=6) or Sh (n=5). Animals were euthanized 7 daysafter BDL. Blood samples were obtained before surgery(BS1) and before euthanasia (BS2) and BR, alanineaminotransferase (ALT), aspartate aminotransferase(AST), alkaline phosphatase (ALP), gammaglutamyltransferase (gGT) and lipid peroxidation were determined. At euthanasia, liver samples were obtainedfor the assessment of lipid peroxidation. Results(media±SD for BS1/BS2 in Sh; BDL; PP+BDL) were,respectively: BR(mg/dL) 0.13±0.05/0.11±0.04;0.35±0.02/8.60±0.15a; 0.13±0.01/0.50±0.08a,b. ALT(U/L)48±7/39±3; 136±10/188±15a; 172±32/211±21a. AST(U/L)131±38/136±22; 385±25/474±40a; 343±49/449±36a.ALP(U/L) 570±24/707±79; 343±1/1047±84a; 510±90/1015±120a. gGT(U/L) 0.2±0.1/0.3±0.1;0.5±0.1/12.6±3.1a; 0.8±0.1/1.5±0.2a,b; (a)p<0.05 vsBS1 and Sh; (b)p<0.05 vs BDL. After 7 days of BDL, BRlevels increased far more in BDL than in PP+BDL,corroborating the inhibition of HO1. Differences in ALT,AST, ALP and gGT were not significant between BDL andPP+BDL, evidencing the establishment of cholestasis in bothgroups. The increase in plasma lipid peroxidation (media ±SD) was higher in PP+BDL than in BDL (368±18% vs177±10%, p<0.05), demonstrating that, undercholestatic conditions, oxidative damage worsens whenBR production is impaired. Similar results were obtainedfor lipid peroxidation in liver tissue. We conclude that BRameliorates oxidative damage induced by BDL,contributing to limit the progression of cholestaticdiseases with oxidative background.