Study Of The Expression Of Substance P And Vasoactive Intestinal Peptide In Oral Lichen Planus

Objective:Oral lichen planus (OLP)is a chronic or subacute inflammatory disease in oral mucosa. OLP seriously affects patient's quality of life because of the protracted course of disease and it's relapse. With a certain malignant transformation rate, OLP was identified by the World Health Organization (WHO) as a precancerous condition. Currently,the etiology and pathogenesis of OLP still remains obscure. Most researchers consider it to be a T Lymphocytes induced autoimmune disease and no specific therapeutic approach is available. It has been observed in clinic that tension, stress and depression may lead to the recurrence and aggravation of OLP, indicating a relationship between the pathogenesis of OLP and neural immune system. Histopathologically, OLP shows hyperkeratosis or parakeratosis, hypergranulosis, acanthosis with irregular thickening, basal cell liquefaction degeneration and band-like inflammatory infiltration mainly of dense lymphocytes below epidermis. Substance P(SP)and vasoactive intestinal peptide(VIP),which can regulate immune and inflammatory reactions,belong to neuropeptides produced by nerve system and some local cells such as macrophages, lymphocytes and mast cells. They are associated with chemotaxying immunocytes, regulating cytokine and relaxing microvascular. Based on clinical and pathological characteristic of OLP, we hypothesized that neuropeptides are involved in the pathogenesis of OLP. This study was planned to examine the expression of SP and VIP in OLP tissue,serum and saliva by immumohistochemistry(IHC) and double-antiboody sandwich enzyme-linked immunosorbent assay (ELISA),and investigate the relationship between them and OLP. Methods:All OLP patients employed in this study were hospitalized in the oral medicine department of the Affiliated Stomatological Hospital of Luzhou Medical College from August 2008 to December 2009. Tissue samples from clinically diagnosed patients were confirmed by histopathology, including 19 oral mucosal tissue samples,13 serum samples and 16 saliva samples. All cases did not receive any hormone therapy before. Besides,19 normal oral mucosal tissue samples,13 normal serum samples and 16 normal saliva samples were chosen as normal control.They were collected from healthy volunteers or patients with gingival surgery and mucosal surgery in the department of oral surgery. The experiments were composed of three parts. PartⅠ:SP and VIP expressions in OLP and normal mucosa were examined by IHC. PartⅡ:The concentration of SP and VIP in serum was assayed by ELISA. PartⅢ:The concentration of SP and VIP in saliva was assayed by ELISA. All data were analyzed by SPSS 13.0 statistical software. Rank test was used to analyze the result of immunohistochemistry. The quantitative data were analyzed between two groups by t test. P<0.05 was considered statistically significant. Results:PartⅠ1. OLP tissues displayed SP positive staining in cytoplasm of supra-basal layers compared to basal layer staining in normal mucosal tissues,the difference was significant, P=0.000(P<0.05) which indicated that the SP expression level was higher in the OLP tissue samples than normal ones. The difference of SP expression in erosive OLP and non-erosive OLP group was not significant P=0.348(P>0.05). 2. VIP expressed mainly in cytoplasm of prickle cell layer in OLP samples except that two cases showed cell membrane staining in prickle cell layer and basal cell layer respectively. VIP expression was not observed in normal mucosal tissues except for some immunoreactivity in the cytoplasm of basal layer cells. the difference between the two groups was significant, P=0.012(P<0.05). Therefore, the expression of VIP was higher in OLP tissues than normal samples. The difference of SP expression between erosive OLP and non-erosive OLP group was not significant P=0.141(P>0.05). PartⅡ: 1.The difference of SP concentration in serum between OLP patients and control group was significant, P=0.014 (P<0.05),which meant serum SP concentration was higher in OLP patients than control group.2.The difference of VIP concentration in serum between OLP patients and control group was not significant, P=0.314 (P>0.05). Therefore, there is no difference regarding the serum concentration of VIP between this two groups. PartⅢ:1.SP concentration in saliva in OLP and control group was 287.83±49.74ng/ml, 256.38±56.77ng/ml respectively and the difference was not significant, P=0.079 (P>0.05).2.The difference of VIP concentration in saliva was significant between OLP and control group, P=0.014 (P<0.05). There is a higher VIP expression in saliva in OLP patients compared to normal people.. Conclusions:1.The expression of neuropeptides SP was increased in the OLP tissue samples and serum, suggesting that SP might be involved in the infiltration and proliferation of lymphocytes in the pathogenesis of OLP,and participate in the chronic inflammatory mechanisms of OLP.2. Increased VIP expression in OLP tissue samples indicated that VIP might be derived mainly from local cells which could promote lymphocytes migration in tissue.3. The expression of VIP was increased in the saliva of OLP patients. Moreover, It'convenient to collect saliva samples in clinic.The saliva concentration of VIP may be helpful to monitor therapy and predict recurrence for OLP patients.