Progress of experimental study on treatment of psoriasis by Chinese medicinal monomer and single or compound recipe in Chinese materia medica.

Psoriasis is a common, chronic, recurrent inflammatory skin disorder whose etiology is still unknown. It is believed that a multiple-gene inheritance is involved and it also involves various factors such as immunity, inflammation, cell proliferation, apoptosis, neural media, etc. Since cytokines are key mediators in inflammation, a number of Chinese medicines (CMs) have been reported to have certain antagonist effects on pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), platelet active factor (PAF) and interleukin-8 (IL-8). Some researches on CMs have made significant breakthroughs in psoriasis by intervening with cytokines. Abnormalities with keratinocyte proliferation and apoptosis are considered to be present in patients with psoriasis and a number of studies show that the mechanism of CMs on psoriasis may be through the inhibition of the keratinocyte proliferation and induction of apoptosis. Other studies also show that the inhibition of fibroblast-secreted cytokines could regulate keratinocyte proliferation and differentiation and reduce the level of Calcitonin gene-related peptide (CGRP) in plasma and in lesions so as to slow down the process of inflammation and proliferation in psoriasis. The most commonly used models for psoriasis are the scaled tails or the vaginal epithelium of mice in China. They were used to observe the histopathological changes after the model mice were treated with CMs with the inhibition on the mitosis of vaginal epithelium or promotion of granular layer in rat tail taken as the indices of clinical efficacy. A variety of signs occur in psoriasis patients with TCM blood-stasis syndrome type and the effect of CMs in activating blood circulation to remove blood stasis on psoriasis suggested that the mechanism of CMs may be partially correlated to hemorrheology and microcirculation. Along with the continuous development of the biosciences, some TCM theories for psoriasis have been confirmed by laboratory studies. However, the exploration into traditional Chinese medicines' biomechanics in psoriasis and the therapeutic mechanism of CMs by integrative medicine still requires further studies.