嚼食檳榔是造成口腔黏膜下纖維化的主要原因，其會造成黏膜上皮萎縮與過量的膠原蛋白堆積在結締組織層中。檳榔素是檳榔中含量最多的植物鹼，其亦被認為與口腔黏膜下纖維化關係密切，以往有關此類研究多從膠原蛋白著手，鮮少有研究探討檳榔成分對金屬蛋白脢與組織蛋白抑制脢的影響。本研究以組織培養法，培養人類頰黏膜纖維母細胞與口腔黏膜下纖維化纖維母細胞，結果發現口腔黏膜下纖維化纖維母細胞有較高TIMP/1的表達，檳榔素40μg/ml以下會提高正常頰黏膜纖維母細胞TIMP/1的表現，酵素電泳拓蹼分析發現檳榔素80μg/ml以上會抑制正常頰黏膜纖維母細胞MMP/2的表現，從本研究結果發現檳榔可能透過此一機轉造成正常黏膜轉變成黏膜下纖維化症。
Oral submucous fibrosis (OSF) is a pre-malignant fibrotic lesion of the mouth in areca quid chewers. It is probably a consequence of disturbances in the hemeostatic equilibrium between synthesis and degradation of extracellular matrix molecules (ECM). To date, there has been little research about the role of tissue inhibitors of metalloproteinase (TIMPs) and matrix metalloproteinases (MMPs) in the pathogenesis of OSF. In the present study, we examined the activity of TIMPs from cells cultured from OSF and normal buccal mucosa. OSF specimens were found to have higher TIMP-1 expression than normal buccal mucosal fibroblasts (BMFs) by Western blots. To verify whether arecoline, a major areca nut alkaloid, could affect TIMP or MMP production by human BMFs, Western blots and gelatine zymography were used. Arecoline was found to elevate TIMP-1 expression at the concentration level under 20μg/ml in a dose-dependent manner. The amount of TIMP-1 was about 2.7 fold at a concentration level of 10μg/ml compared with control. From gelatin zymograms, the main gelatinolytic proteinase secreted by the human BMFs was MMP-2, and only minimal amounts of MMP-9 could be detectable from zymogram. In addition, arecoline was found to inhibit MMP-2 secretion and production at the concentration level of 40μg/ml. The gelatinolytic activity of MMP-2 was about 54% at a concentration level of 80μg/ml compared with control. Taken together, it was found that arecoline acted as not only an inhibitor on gelatinolytic activity of MMP-2, but also a stimulator for TIMP-1 activity. These synergistic effects may contribute to the ECM components accumulation in the areca quid associated OSF.
