Expression Of Platelet-Activating Factor Receptor In The Cutaneous Inflammation System And The Intervention Of Drugs

The cutaneous anaphylaxis inflammation is a special kind of allergy. This antigen-antibody reaction always induces inflammatory cells releasing inflammatory factors, which will bring on a series of inflammatory reactions by coordinated intensification effects. It has been reported that PAF (Platelet-Activation Factor ) and its receptors involved in the function of KC (Keratinocyte) and cutaneous inflammation, play an important role in inflammatory skin disease. KC can be activated by PAF and lymphoid factors released from activated T cell. For example, cytokine, as well as ICAM-1 and antigen to express can be induced by IFN-γ. Moreover, UV irradiation and the exogenous heat stimulation can cause the acute damage of epidermis, lead to oxidative stress and cytokines secretion from KC and releasing of PAF from other cutaneous cells.Today much attention has been paid to the cutaneous inflammation and PAF receptor, but the study has just started on abroad. It is very important and necessary to explore the expression characteristics of the PAF receptor in skin tissue and KC, observe the changes of cytokines secreted by KC. In this study, the characteristics have been investigated, such as expression of PAF-R and the role in the cutaneous inflammation. The regulation effects of some drugs (Cetirizine, Tetramcthyl-pyrazine) on the expression of PAF receptor in the cutaneous inflammation were compared to the positive control drug Ginkgolide B.Part 1 :The expression character of PAF-R in KC1. The results of immunohistochemistry showed that the PAF-R resulted in selective binding to the epidermis in a granular pattern on keratinocyte membranes and cytoplasm, most intense on the suprabasal cells, while it was negative in dermis and endermic tissue. The similar phenomenon appeared on HaCaT cell.2. The results of RT-PCR showed that both PAF-R transcriptⅠand PAF-R transcript Ⅱwere expressed in human skin tissue, HaCaT cells, and KC. The expressions of transcript Ⅱ yielded relatively more product. The PAF-R mRNA was not found in fibroblasts. 3. The expression of PAF-R increased greatly treated by 0.1% Saponin in HaCaT cells. And the average fluorescent intensity in cellular was 4.82 folds than in the membrane (p<0.01)4. Edema emerged after 2h in rat skin by i.p. PAF. And then the soaking neutrophils appeared around the dermis vein. The amount of soaking inflammatory cells was correlated with time and the peak time is 6h. The edema began to lighten after 24h. A few inflammatory cells could be seen. The positive signal of PAF-R was located on the membrane of KC, which existed both in normal and inflammatory epidermis, and the later was more extensive than the former.Part 2 The character of KC in the cutaneous inflammation and the intervention of drugs1. HaCaT cells were cultured with cPAF100nM, the cell livability was 114.3% of the control group (p<0.05). cPAF could increase the secretion of IL-6 and IL-8 greatly (p<0.05). The membrane expression of ICAM-1 was 2.96 times as much as that of the control. 2. How the HaCaT cells activated by cPAF involved in the inflammatory reaction was investigated. The secretion of IL-6 and IL-8 were increased by IFN-γ. The secretion of IL-6 was dose depended with IFN-γbetween 0~80ng/mL. The secretion of IL-8 reached the peak of 979.2±44.7(p<0.05) when the IFN-γconcentration was 40ng/mL, and downregulated when IFN-γ was 80ng/mL. The expression of ICAM-1 dose-dependently upregulated in the activated HaCaT cells with IFN-γ.3. The mechanism was investigated of HaCaT cells involved in cutaneous inflammation. The results showed that UVA (1~6min) irradiation had no significant effect on IL-6 and IL-8 in normal and cPAF-activated HaCaT cell (p>0.05). But UVB (10~80s) irradiation had time-depended effect on normal and experimental group. After the normal and cPAF-activated HaCaT cell was irradiated by UVB(10,30,50s), the secretion of IL-6 and IL-8 dose-dependently increased. The effect on the cPAF-activated HaCaT cells was significant (p<0.05).4. The MTT result showe...