Immunity system, nerve system ・ endocrine system in periodontitis

近年来，有报道称神经营养因子可产生非神经细胞，而非神经细胞是外周神经元的靶细胞。本研究探讨了神经生长因子（NGF）、脑源性神经营养因子（BDNF）和神经营养因子-3 （NT-3）及其受体是否分别为TRKA、TRKB和TRKC。在培养的人牙周韧带细胞（HPDL）、人牙龈成纤维细胞（HGF）、人牙龈角质形成细胞（HGK）、人牙髓细胞（HPC）和人皮肤成纤维细胞（HSF）中，采用聚合酶链反应（PCR）法检测了3种具有代表性的神经营养因子，即神经生长因子（NGF）、脑源性神经营养因子（BDNF）和神经营养因子-3 （NT-3）及其受体TRKA、TRKB和TRKC的mRNA编码。所有神经啡肽和受体几乎在培养的牙周组织细胞中表达。HGK中的BDNF、HPDL中的TRKB、HGK中的NT-3和HPC-2中的TRKC几乎没有mRNA表达。接下来，我们研究了白细胞介素-1 β (IL-1)对各种神经营养因子及其受体mRNA表达的影响。HPC中TRKA和HPDL中NT-3呈升高趋势。但这些结果几乎都不显著。这些结果可能表明神经营养因子在牙周组织破坏阶段不起作用。即神经营养因子可促进牙周组织的再生。我们还通过原位杂交研究了体内牙周组织中各种神经营养因子及其受体mRNA的表达。原位杂交结果与体外杂交结果吻合。一些神经营养因子及其受体分布在表皮的不同部位。这表明神经营养素可能以旁分泌的方式起作用。这些结果表明，神经营养因子可能在牙周病状态的改变中起重要作用。

Recently, it has been reported that neurotrophic factors produced non-neural cells which are target cells of peripheral neurons. This study investigated whether nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) and their receptors respectively TRKA, TRKB and TRKC.In a cultured human periodontal ligament cells (HPDL), human gingival fibroblast cells (HGF) and human gingival keratinocytes (HGK), human dental pulp cells (HPC) and human skin fibroblasts (HSF), the mRNA encoding three representative neurotrophins, namely, verve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) and their receptors respectively TRKA, TRKB and TRKC were detected by polymerase chain reaction (PCR) method. All neurotorophins and receptors expressed in almost of cultured cells from periodontal tissue. BDNF in HGK, TRKB in HPDL, NT-3 IN HGK and TRKC in HPC-2 were not demonstrated mRNA almostly.Next, we investigated that the effects of interleukin-1 beta (IL-1) on mRNA demonstration of various neurotrophins and their receptors. TRKA in HPC and NT-3 in HPDL were shown a tendency to increase. But almost of these results might not be significantly. These results may show that neurotrophins do not act in the phase of destroy of periodontal tissue. Namely neurotrophins may promote at the regeneration of periodontal tissue.We also investigated that demonstration of mRNA of various neurotrophins and their receptors in periodontal tissue in vivo by in situ hybridization. Results of in situ hybridization were matched the results of in vitro experiment. Some neurotrophins and their receptors however were showed that various sites in the epidermis. This shows that neurotrophins may act in a paracrine manner.These results show that neurotrophins may act as important factor in the change of periodontal disease state.