Abstract:

Objective To evaluate the influence of narrow-band ultraviolet B on lesional microvessel density （MVD）, vascular endothelial growth factor （VEGF）, matrix metalloproteinases 2 （MMP-2） as well as on serum VEGF in patients with psoriasis vulgaris （PV）. Methods Fifteen patients with PV were recruited into this study with 10 normal human controls. All patients received NB-UVB phototherapy thrice a week for 4-5 weeks. Prior and after the treatment, psoriasis area and severity index （PASI） was calculated, tissue specimens were taken from non-photoexposed lesions, and sera samples were obtained from these patients. Then, MVD and the expression level of VEGF and MMP-2 were measured by immunohistochemical labeled dextran polymer （LDP） method in the tissue specimens. Also, the serum level of VEGF was tested by enzyme-linked immunosorbent assay （ELISA）. Results PASI score remarkably decreased in patients after the phototherapy （t = 13.35, P < 0.01）. The MVDs were 20.52 ± 5.02, 7.33 ± 1.24 and 4.26 ± 0.79 capillaries per high power field （400 × amplification）, in psoriatic lesions before treatment, after treatment, and normal control tissues, respectively, with a significant difference among the three groups （F = 97.57, P < 0.05）, and a significant increase was observed in the lesions before treatment compared with those after treatment and normal controls. The serum level of VEGF was 307.55 ± 121.65 ng/L in psoriatic lesions before treatment, significantly higher than that after treatment （163.92 ± 95.57 ng/L）, and in normal control skin （139.78 ± 79.06 ng/L）, whereas there was no significant difference between the latter two groups （P > 0.05）. The positivity rate of MMP-2 was similar among the three groups without statistical difference （P > 0.05）. In psoriatic patients, a positive correlation was observed among PASI score, MVD, lesional and serum VEGF levels （P < 0.05）, also among the MVD, VEGF and MMP-2 levels in lesions （P < 0.05）, but lesional MMP-2 was unrelated to PASI score or serum VEGF （both P > 0.05）. Conclusions NB-UVB may regulate superficial dermal microvascular proliferation by acting on the expression of VEGF in sera and lesions of psoriatic patients. VEGF and MMP-2 may both participate in the proliferation process of microvessels, while MMP-2 is unlikely to be involved in the therapeutic mechanism of NB-UVB.

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