This study investigated whether the presence of Mycoplasma fermentans (M. fermentans) in the temporomandibular joint (TMJ) could be associated with the pathology of temporomandibular joint disorders (TMD). One hundred fifteen synovial fluid (SF) samples from patients with TMD were evaluated for the presence of DNA of M. fermentans by polymerase chain reaction (PCR) assay. Specific antibody against M. fermentans was also detected in the SF as well as sera by Western blot analysis. M. fermentans DNA was identified in 37.4% of the SF samples from the TMD patients. There was no difference between PCR-positive and -negative rate regarding sex and disease categories, e.g., internal derangement (ID) and osteoarthritis (OA). However, the prevalence of M. fermentans DNA in ID patients was higher in elderly patients (73.3%) than in younger patients (31.8%). Anti-M. fermentans immunoreactivities (IgG) specific for lipoproteins with various molecular sizes, 56 kilo-Dalton (kDa), 48 kDa, 38 kDa, and 29 kDa, were also identified in the SF. The immunoreactivity was also detected in the patients'sera. The reactivity patterns of the anti-M. fermentans antibodies were, however, different between the SF and the sera; reactivities to 48 kDa and 29 kDa lipoproteins were prominent in the former, while the reactivities to those of 56 kDa, 48 kDa, and 29 kDa were evidently increased in the latter. The presence of specific DNA and antibody for M. fermentans in the TMJ implies that M. fermentans could possibly induce joint specific immunoreaction, thus perpetuating the inflammatory reaction in the diseased TMJ.

We report the in vitro establishment of a highly stable green fluorescent protein (GFP) -expressing transfectant of a highly-invasive human tongue squamous cell carcinoma (HTSCC) cell line, SAS-H1. The fluorescent cells permitted the visualization of tumor growth, local invasion, micrometastasis and cervical lymph node metastasis after submucosal injection into the tongues of nude mice. SAS-H1 cells were transfected with the pEGFP-N1 expression vector containing the GFP and neomycin resistance genes. Stable SAS-H1 clones expressing high levels of GFP were selected stepwise in vitro in levels of geneticin (G418) of up to 3,500 μg/ml. Subsequent early stages of local invasion and micrometastasis were visualized by GFP fluorescence in a primary tumor of the tongue. Furthermore, lymph node metastasis was confirmed for all of the orthotopic transplants in mice. However, no distant metastases, including those of lung and liver, were observed. Thus, this model should be useful for studying the metastatic process and for evaluating anti-metastasis agents in pre-clinical trials.

OBJECTIVETo study the adaptive alterations of elastic fibers in the bilaminar zone (BZ) of rabbit temporomandibular joint (TMJ) following disc displacement.

METHODSTwenty-eight Japanese white rabbits were used in this study. The right temporomandibular joints of 20 of 28 rabbits were subjected to the surgical procedure of anterior disc displacement (ADD). Four rabbits in the surgical group were sacrificed at 2, 4, 6, 8 and 12 weeks after operation. Their temporomandibular joints were studied histochemically.

RESULTSElastic fibers were reduced in number and ran irregularly in the superior lamina of BZ from ADD rabbits. The jungly elastic fibers (EFs) could still be seen at 2 weeks after operation. At 4 weeks, the number of EFs decreased significantly; EFs lost their jungly arrangement and were shaped like rough dots, of which the arrangement and the lengths were different. Six weeks after operation, many EFs were replaced by distorted, uneven, non-oriented fine EFs, distributed unevenly and some thick or fine EFs that ran irregularly. The number of EFs decreased further and their arrangement was more deranged at 8 weeks. At 10 and 12 weeks, EFs in the superior lamina of BZ were similar to those at 8 weeks.

CONCLUSIONOur results show that EFs lost their function as well as their distribution and arrangement after disc displacement.

Adaptation, Physiological ; Animals ; Behavior, Animal ; Elastic Tissue ; pathology ; Extracellular Matrix ; pathology ; Joint Dislocations ; pathology ; Rabbits ; Temporomandibular Joint Disc ; pathology ; Temporomandibular Joint Disorders ; pathology

OBJECTIVETo study the chondrocyte apoptosis in rabbit temporomandibular joint after anterior disc displacement.

METHODSExperimental anterior disc displacement was induced surgically in 20 Japanese rabbits without opening their temporomandibular joint bursas. Histopathologic and apoptotic (TUNEL) analysis was used to evaluate the changes in articular cartilage, disc and synovium.

RESULTSCondyle chondrocyte showed apoptosis most obviously at 1 or 2 weeks after surgery, and apoptotic cells concentrated in proliferative zone and hypertrophic zone. 4 or 6 weeks after surgery, the joint went into a remodelling period.

CONCLUSIONSChondrocyte apoptosis in temporomandibular joint will be activated after anterior disc displacement, which initiates the remodelling in temporomandibular joint.

Animals ; Apoptosis ; Chondrocytes ; pathology ; In Situ Nick-End Labeling ; Joint Dislocations ; physiopathology ; Rabbits ; Temporomandibular Joint ; physiopathology ; Temporomandibular Joint Disc ; physiopathology

OBJECTIVETo study the gene expression changes in extracellular matrix of condylar cartilage following disc anterior displacement of rabbit TMJ.

METHODSThe right sides of 28 joints in 40 rabbits were subjected to surgical operation of disc displacement. The condylar Collagen II and Aggrecan mRNA expression were detected by in situ hybridization.

RESULTSCollagen II and Aggrecan mRNA mainly expressed in the lower zone of condylar chondrocyte. Aggrecan mRNA decreased faster than collagen II following disc displacement, and adjusted to normal later.

CONCLUSIONAnterior disc displacement leads to alteration of extracellurar matrix gene expression in the condylar chondrocyte, which means the start of remodeling.

Aggrecans ; Animals ; Bone Remodeling ; Cartilage, Articular ; cytology ; Chondrocytes ; metabolism ; Collagen Type II ; biosynthesis ; genetics ; Extracellular Matrix ; metabolism ; Extracellular Matrix Proteins ; biosynthesis ; genetics ; Female ; In Situ Hybridization ; Lectins, C-Type ; Male ; Mandibular Condyle ; cytology ; metabolism ; Proteoglycans ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Rabbits ; Temporomandibular Joint ; cytology ; metabolism ; Temporomandibular Joint Disc ; surgery ; Temporomandibular Joint Disorders ; etiology ; genetics ; metabolism