Abstract: Background: Heme oxygenase-1 is a kind of antioxidative enzyme. A dinucleotide GT repeat in promoter region of Human HO-1 gene shows a length polymorphism that may modulates the level of gene transcription. Therefore this polymorphism phenomenon may associate with the development of essential hypertension. Objective: (1) To investigate the relationship between the length polymorphism of GT repeat in HO-1 promoter area and essential hypertension.(2) To observe if this polymorphism will affect the levels of bilirubin, TNF-? and IL-10 in plasma. (3) To evaluate the effect of the genotypes in the plasma levels of bilirubin, TNF-? and IL-10. Methods: The HO-1 gene GT dinucleotide repeat polymorphism in promoter area was evaluated in 102 EH patients and 134 healthy controls. The genotypes were analyzed by PCR and polyacrylamide gel electrophoresis. Plasma levels of TNF-? and IL-10 were obtained by ELISA methods. Bilirubin levels were measured by automatic chemistry analyzer. Results: (1) The plasma levels of bilirubin, TNF-? and IL-10 in EH group were higher than in control group. (the levels of bilirubin, TNF-? and IL-10 in EH group were 12.53?4.41umol/L; 2.22?0.57ng/ml; 40.87?5.53pg/ml respectively VS control group: 11.46?5.53umol/L; 1.97?0.47ng/ml; 38.17?4.46pg/ml p?0.05 ) (2) The long allele with ≥32 (GT)n repeats (L allele) was found more frequently in hypertension group(26.5% vs 14.6% X2 =10.42, p?0.05). (3) There was no significant difference to be found between the genotypes and the plasma levels of TNF-? and IL-10.The plasma bilirubin levels in the cases carrying with long allele were higher than the cases carrying with short allele. Conclusions: The long allele of HO-1 genotype may be associated with the development of essential hypertension. The levels of bilirubin, TNF-? and IL-10 in plasma may affect the development of EH .

Key words: hypertension, heme oxygenase-1, polymorphism