Determination of antioxidant capacity and 8-iso-prostaglandin F2α levels in patients with psoriasis and their significance

Abstract

Objective To determine the levels of 8-iso-prostaglandin F2α (PGF2α) in sera and lesions as well as antioxidant capacity in sera of psoriatic patients,and to assess their correlations with disease severity.Methods Serum and skin tissue samples were collected from 15 healthy controls and 50 patients with psoriasis vulgaris.Spectrophotometry was performed to determine the levels of total antioxidant capacity (T-AOC) and the activities of antioxidant enzymes such as superoxide dismutase (SOD),catalase (CAT) and glutathione peroxidase (GSH-Px) in serum samples.Enzyme-linked immunosorbent assay (ELISA) and immunohistochemical SP method were carried out to detect the expression level of 8-iso-PGF2α in the serum and tissue specimens respectively.Results The psoriatic patients showed a significant decrease in the serum level of TAOC ((12.78 ± 7.75) U/ml vs. (23.17 ± 8.81) U/ml,P＜ 0.01) as well as the activities of SOD ((28.91 ±9.35) U/ml vs.(51.36 ± 7.92) U/ml,P＜ 0.01) and GSH-Px ((180.64 ± 47.70) U vs.(244.20 ± 66.68) U,P ＜ 0.01 ) compared with the healthy controls.The serum T-AOC level and SOD activity were lower in patients with severe psoriasis than those with mild or moderate psoriasis ((9.06 ± 5.30) U/ml vs. (15.27 ± 8.18) U/ml,(21.63 ± 5.28) U/ml vs. (33.76 ± 8.28) U/ml,both P＜ 0.01 ),while there was no significant difference in the activity of GSH-Px between patients with severe and mild or moderate psoriasis.The serum CAT activity was significantly higher in patients with mild or moderate psoriasis than in the healthy controls and patients with severe psoriasis ( (36.92 ± 11.31 ) U/ml vs.( 28.55 ± 8.51 ) U/ml and (24.15 ± 9.36 ) U/ml,P ＜ 0.05 and 0.01 ).Increased serum and lesional 8-iso-PGF2α levels were observed in psoriatic patients compared with the healthy controls ( (88.77 ± 25.27) ng/L vs.(38.34 ± 8.94) ng/L,0.0186 ± 0.0082 vs.0.0027 ± 0.0014,both P ＜ 0.01),as well as in patients with severe psoriasis compared with those with mild or moderate psoriasis (( 114.24 ±13.93) ng/L vs.(71.78 ± 14.35) ng/L,0.0279 ± 0.0027 vs.0.0125 ± 0.0030,both P＜ 0.01 ).The psoriasis area and severity index (PASI) score was negatively correlated with T-AOC level,SOD and CAT activities (r =-0.384,-0.573 and -0.444,all P ＜ 0.01 ),positively correlated with serum and lesional 8-iso-PGF2α levels (r =0.710,0.783,both P ＜ 0.01 ),and uncorrelated with GSH-Px activity.None of the parameters was correlated with the course of disease.Conclusion The serum and lesional levels of 8-iso-PGF2α may be a more sensitive marker for oxidative damage and disease severity. Key words: Psoriasis; Oxidative stress; Superoxide dismutase; Catalase; Glutathione peroxidase; Isoprostanes