Xj Zhou

The pathogenesis of oral lichen planus

Both antigen-specific and non-specific mechanisms may be involved in the pathogenesis of oral lichen planus (OLP). Antigen-specific mechanisms in OLP include antigen presentation by basal keratinocytes and antigen-specific keratinocyte killing by CD8(+) cytotoxic T-cells. Non-specific mechanisms include mast cell degranulation and matrix metalloproteinase (MMP) activation in OLP lesions. These mechanisms may combine to cause T-cell accumulation in the superficial lamina propria, basement membrane disruption, intra-epithelial T-cell migration, and keratinocyte apoptosis in OLP. OLP chronicity may be due, in part, to deficient antigen-specific TGF-beta1-mediated immunosuppression. The normal oral mucosa may be an immune privileged site (similar to the eye, testis, and placenta), and breakdown of immune privilege could result in OLP and possibly other autoimmune oral mucosal diseases. Recent findings in mucocutaneous graft-versus-host disease, a clinical and histological correlate of lichen planus, suggest the involvement of TNF-alpha, CD40, Fas, MMPs, and mast cell degranulation in disease pathogenesis. Potential roles for oral Langerhans cells and the regional lymphatics in OLP lesion formation and chronicity are discussed. Carcinogenesis in OLP may be regulated by the integrated signal from various tumor inhibitors (TGF-beta 1, TNF-alpha, IFN-gamma, IL-12) and promoters (MIF, MMP-9). We present our recent data implicating antigen-specific and non-specific mechanisms in the pathogenesis of OLP and propose a unifying hypothesis suggesting that both may be involved in lesion development. The initial event in OLP lesion formation and the factors that determine OLP susceptibility are unknown.

Matrix metalloproteinases and their inhibitors in oral lichen planus

Background: Oral lichen planus (OLP) is characterized by a sub‐epithelial lymphocytic infiltrate, basement membrane (BM) disruption, intra‐epithelial T‐cell migration and apoptosis of basal keratinocytes. BM damage and T‐cell migration in OLP may be mediated by matrix metalloproteinases (MMPs).

Immunohistochemical study of apoptosis-related proteins and cell proliferation markers in oral lichen planus.

Corticosteroids are widely used today in the medical treatment of many chronic illnesss. It has hem well docunnented that corticosteroids affect hone metabolism and this rnaie concemas as so the effect of coeticosteroid treatent on orthodontic tooth movemiernt. The aimn of this study was to determine Ithe effect of an elevated physiologic level of corticosteroid on bone rmnodeling daring orthodontic movement. Twelve 9-weak old adult male Wisuar rate were divided into two groups- a corticosteroid treated group (n=6) and a control group (n=6). The corticosteroid treate group was admiinistered ltngik of oral prednisolone daily for a 12-day induction period, while the control group received the equivalent volumes of saline for the tame liTme period. Following thin induction period, an orthodontiC appiance was ligated between the maxillary first left molar and two nmaxillary central incisors such thata menia force of 30g wasW T R W generated. The molar on the right skide was used an the son-appliance control. All sanimals were sacrificedIT WDR after 12 days of appliance wear. The magnitude of tooth mnovement was recoorded. Maxillse were fixed, demineralised and processed to paraffin. Sagittal sections of the first molar were staned with harmatoxylin and cosin and for turtrate-resistant acid phosphatase (TRAP) activity. For thin dose of prednisolone, there are no significant differences (p<0.05) in the magnitude of tooth imovement between the treated and control groups. Steroid treaed rats displayed lens root resorption along the length of the root on the coespressive side as well as fewer TRAP positive cells widthin the PDL space of the comspressive side, conmpaed to the non-sterid control (p.Z0.05). There was more TRAP activity recorded along the tension-side alveolar bone surface (cervcal third) in the steroid treated rats comspared to the son steroid controls (pr0O05). The rate of orthodontic movements was unaffected by lessgIsa of orednisolone. The easth of root renemtion alon th menial comprenson side and the TRAP activity at the comoression side PDL were both reduced. suagenlise that a susorenion of clastic activity had taken place. This study was supported by an ADRF grat.

Cellular microenvironments in oral lichen planus.

Corticosteroids are widely used today in the medical treatment of many chronic illnesss. It has hem well docunnented that corticosteroids affect hone metabolism and this rnaie concemas as so the effect of coeticosteroid treatent on orthodontic tooth movemiernt. The aimn of this study was to determine Ithe effect of an elevated physiologic level of corticosteroid on bone rmnodeling daring orthodontic movement. Twelve 9-weak old adult male Wisuar rate were divided into two groups- a corticosteroid treated group (n=6) and a control group (n=6). The corticosteroid treate group was admiinistered ltngik of oral prednisolone daily for a 12-day induction period, while the control group received the equivalent volumes of saline for the tame liTme period. Following thin induction period, an orthodontiC appiance was ligated between the maxillary first left molar and two nmaxillary central incisors such thata menia force of 30g wasW T R W generated. The molar on the right skide was used an the son-appliance control. All sanimals were sacrificedIT WDR after 12 days of appliance wear. The magnitude of tooth mnovement was recoorded. Maxillse were fixed, demineralised and processed to paraffin. Sagittal sections of the first molar were staned with harmatoxylin and cosin and for turtrate-resistant acid phosphatase (TRAP) activity. For thin dose of prednisolone, there are no significant differences (p<0.05) in the magnitude of tooth imovement between the treated and control groups. Steroid treaed rats displayed lens root resorption along the length of the root on the coespressive side as well as fewer TRAP positive cells widthin the PDL space of the comspressive side, conmpaed to the non-sterid control (p.Z0.05). There was more TRAP activity recorded along the tension-side alveolar bone surface (cervcal third) in the steroid treated rats comspared to the son steroid controls (pr0O05). The rate of orthodontic movements was unaffected by lessgIsa of orednisolone. The easth of root renemtion alon th menial comprenson side and the TRAP activity at the comoression side PDL were both reduced. suagenlise that a susorenion of clastic activity had taken place. This study was supported by an ADRF grat.