Expression of bone histomorphometry parameters in rabbit condyle during mandibular forward positioning / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the changes of bone histomorphometry parameters in condyle of rabbits during mandibular forward positioning.</p><p><b>METHODS</b>Forty rabbits with eight weeks of age were simple randomly divided into the experimental group (n = 24) and control group (n = 16).Mandibles of rabbits in the experimental groups were induced to forward position by a functional appliance.The experimental group and control group were sacrificed after 2 and 4, 8, 12 weeks.The specimens from right tempromandibular joints were processed for undemineralised sections.These sections were used for fluorescent microscopy observation and the measurement of bone histomorphometry.</p><p><b>RESULTS</b>At 8 week bone-volume fraction [(75.83 ± 1.10)%], trabecular thickness [(103.28 ± 2.89) µm], trabecular number [(2.86 ± 0.06) mm(-1)], mineral apposition rate [(2.32 ± 0.02) µm/d] and index of osteoblast [(30.20 ± 0.47) N/mm(2)] in subchondral region of the cartilage in the experimental group were significantly increased compared with the age-matched controls [respectively (64.00 ± 1.54)%, (87.00 ± 1.13) µm, (1.84 ± 0.08) mm(-1), (1.69 ± 0.02) µm/d and (21.07 ± 0.59) N/mm(2)] (P < 0.05). However, trabecular separation [(170.00 ± 2.25) µm] was lower than those in the controls [(241.50 ± 1.57) µm] with significant difference(P < 0.05). There was no significant difference in the bone histomorphometry parameters of the central region between the experimental group and the age-matched control group (P > 0.05).</p><p><b>CONCLUSIONS</b>The pattern of bone histomorphometry parameters expression in subchondral region has a high correlation with the adaptive remodeling of the condyle after functional appliance.</p>

Construction of vectors encoding mouse Dishevelled 2 and its expression in RAW264.7 cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To construct the recombinant vectors that express mouse Dishevelled 2 (Dvl2), and to evaluate its expression level in transfected RAW264.7 cells.</p><p><b>METHODS</b>A pair of specific primers were designed according to the mouse Dvl2 cDNA sequence published in GenBank. Total RNA of RAW264.7 cells was extracted, and open reading frame of Dvl2 was obtained by RT-PCR, which was then cloned into pEZ-M29 plasmid. Electrophoresis after macrorestriction and DNA sequence analysis were used to identify the reconstructed plasmids. After transient transfection via liposome, the transfection of RAW264.7 cells was confirmed under a fluorescence microscope, and the expression level of Dvl2 was evaluated by real-time RT-PCR.</p><p><b>RESULTS</b>The recombinant plasmid containing mouse Dvl2, namely pEZ-M29/ Dvl2, was successfully constructed, and confirmed by DNA sequence analysis. After 48 h of tranfection, the expression of enhanced green fluorescene protein was observed under a fluorescence microscope, and real-time RT-PCR analysis revealed that the Dvl2 mRNA level was prominantly elevated in the transient transfected RAW264.7 cells.</p><p><b>CONCLUSION</b>The recombinant plasmids pEZ-M29/Dvl2 are successfully constructed and can elevate the Dvl2 mRNA level in the transient transfected RAW264.7 cells, which can be used in further studies aiming at revealing the functional significance of Dvl2 in the osteoclastogenesis.</p>

Effect of hydrostatic pressure on ultrastructure of synovial fibroblasts from rat temporomandibular joint / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the role of apoptosis in the remodeling of temporomandibular joint (TMJ) under pressure.</p><p><b>METHODS</b>Synovial fibroblasts obtained from rat temporomandibular joint were subjected to different hydrostatic pressure for 12 h. Changes of ultrastructure were observed by transmission electron microscope.</p><p><b>RESULTS</b>At 30 kPa, the ultrastructure of synovial fibroblasts showed no obvious changes. At 60 kPa, the chromatin was condensated, the baryon took on crescent and the mitochondria seemed varicose. At 90 kPa, the apoptosis-like body was wrapped by membrane and embedded in the high density chromatin.</p><p><b>CONCLUSIONS</b>Apoptosis-like change took place in ultrastructure of synovial fibroblasts under hydrostatic pressure, and the degree of the change was related to the hydrostatic pressure exerted.</p>

Central mechanisms of masticatory muscle pain induced by occlusal interference / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study c-fos and substance P expression in the central nervous system following mechanical and chemical nociceptive stimulation to the masseters in rats with occlusal interference.</p><p><b>METHODS</b>Occlusal interference was made by bonding a 2 mm long dentin screw in the pulp cavity of the first maxillary molar in the left side. Seven days after occlusal interference, the rats in occlusal interference and mechanical stimulus group and mechanical stimulus control group were light anesthetized and nociceptive mechanical stimulus were applied to the ipsilateral masseter. Pain response was recorded and all the animals were killed 2 hours later. The rats in the other two groups were deep anesthetized and 100 microL 5% formalin was injected into the ipsilateral masseter, killed 2 hours later. The brainstem and cervical spinal cord were processed c-fos and substance P immunoreactivity and data were quantitatively analyzed.</p><p><b>RESULTS</b>Both mechanical and chemical stimulus to the ipsilateral masseter induced increasing neuronal c-fos expression in the trigeminal nucleus and in the cervical spinal dorsal horn in occlusal interference and mechanical stimulus group and occlusal interference and chemical stimulus group (P < 0.05). Following mechanical stimulation to the ipsilateral masseter, substance P expression in the trigeminal nucleus transition zone was increased in occlusal interference and mechanical stimulus group (P < 0.05).</p><p><b>CONCLUSION</b>The central neuronal sensitization in the brainstem may play an important role in the masticatory muscle pain induced by occlusal interference.</p>

Association between infection of different strains of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival plaque and clinical parameters in chronic periodontitis / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>OBJECTIVE</b>The aim of this study was to investigate subgingival infection frequencies of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans strains with genetic variation in Chinese chronic periodontitis (CP) patients and to evaluate its correlation with clinical parameters.</p><p><b>METHODS</b>Two multiplex polymerase chain reaction (PCR) assays were developed to detect the 16SrDNA, collagenase (prtC) and fimbria (fimA) genes of P. gingivalis and the 16SrDNA, leukotoxin (lktA) and fimbria-associated protein (fap) genes of A. actinomycetemcomitans in 60 sulcus samples from 30 periodontal healthy subjects and in 122 subgingival plaque samples from 61 patients with CP. The PCR products were further T-A cloned and sent for nucleotide sequence analysis.</p><p><b>RESULTS</b>The 16SrDNA, prtC and fimA genes of P. gingivalis were detected in 92.6%, 85.2% and 80.3% of the subgingival plaque samples respectively, while the 16SrDNA, lktA and fap genes of A. actinomycetemcomitans were in 84.4%, 75.4% and 50.0% respectively. Nucleotide sequence analysis showed 98.62%~100% homology of the PCR products in these genes with the reported sequences. P. gingivalis strains with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ were predominant in deep pockets (>6 mm) or in sites with attachment loss > or =5 mm than in shallow pockets (3~4 mm) or in sites with attachment loss < or =2 mm (P<0.05). P. gingivalis strains with prtC+/fimA+ also showed higher frequency in gingival index (GI)=3 than in GI=1 group (P<0.05).</p><p><b>CONCLUSION</b>Infection of P. gingivalis with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ correlates with periodontal destruction of CP in Chinese. Nonetheless P. gingivalis fimA, prtC genes and A. actinomycetemcomitans lktA gene are closely associated with periodontal destruction, while A. actinomycetemcomitans fap gene is not.</p>

Effect of disc displacement on mRNA expression of urokinase plasminogen activator and its inhibitor-1 in synovial tissues / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of anterior disc displacement on the expression of urokinase plasminogen activator and its inhibitor-1 (uPA/PAI-1) in synovial tissues.</p><p><b>METHODS</b>Forty Japanese white rabbits were used in this study. The animals were killed at 4 days, 1, 2, 4, 8 and 12 weeks postoperatively, respectively. In situ hybridization technology was applied to detect the expression of uPA/PAI-1 mRNA in synovial membrane.</p><p><b>RESULTS</b>In normal synovial tissues, synovial lining cells and a few fibrosblasts with mild positive staining were occasionally seen. More synovial lining cells and fibrosblasts with moderate postive signals were found 1 week after operation. Since then, the degree of staining for uPA/PAI-1 increased gradually. By the end of 12 weeks postoperatively, strong signals of uPA/PAI-1 mRNA were detected.</p><p><b>CONCLUSION</b>There is a harmonized uPA/PAI-1 system existing in synovial tissues. The high expression of uPA and PAI-1 mRNA in synovial tissues indicates that the uPA/PAI-1 system may play an important role in the process of synovitis resulted from anterior disc displacement.</p>

Infection frequency of Epstein-Barr virus in subgingival samples from patients with different periodontal status and its correlation with clinical parameters / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>OBJECTIVE</b>To detect the infection frequencies of different genotypes of Epstein-Barr virus (EBV) in subgingival samples from chronic periodontitis (CP) patients, and to discuss the correlation between infection with EBV and clinical parameters.</p><p><b>METHODS</b>Nested-PCR assay was used to detect EBV-1 and EBV-2 in subgingival samples from 65 CP patients, 65 gingivitis patients and 24 periodontally healthy individuals. The amplicons were further identified by restriction fragment length polymorphism analysis (RFLP) with endonucleases Afa I and Stu I. Clinical parameters mainly included bleeding on probing (BOP), probing depth (PD), attachment loss (AL) in six sites of the dentition.</p><p><b>RESULTS</b>In CP patients, gingivitis and periodontally healthy individuals, the infection frequencies were 47.7%, 24.6% and 16.7% for EBV-1, and 15.4%, 7.7% and 0% for EBV-2, respectively. In 2 out of the 65 CP patients co-infection of EBV-1 and EBV-2 was found. The positive rate of EBV-1 in chronic periodontitis patients was higher than that in gingivitis patients (P=0.01) and periodontally healthy individuals (P=0.01). But no significant difference was shown in EBV-1 frequency between gingivitis patients and healthy individuals (P>0.05) or in EBV-2 frequency among the three groups (P>0.05). In CP patients, higher mean BOP value was found in EBV-1 or EBV-2 positive patients than that in EBV negative ones (P<0.01), but with no statistical difference in the mean PD or AL value between EBV positive and negative patients (P>0.05). After initial periodontal treatment, 12 out of the 21 EBV-1 positive CP patients did not show detectable EBV-1 in subgingival samples.</p><p><b>CONCLUSION</b>nPCR plus RFLP analysis is a sensitive, specific and stable method to detect EBV-1 and EBV-2 in subgingival samples. Subgingival infection with EBV-1 is closely associated with chronic periodontitis. Infection of EBV in subgingival samples was correlated with BOP.</p>

Gene expression of fibrinolytic factors urokinase plasminogen activator and plasminogen activator inhibitor-1 in rabbit temporo-mandibular joint cartilage with disc displacement / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temporomandibular disorders have not yet been clarified. The aims of this study were to investigate the gene expression of fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the articular cartilage of rabbit temporomandibular joint (TMJ) with disc displacement (DD) and to probe the relationship between fibrinolytic activity and cartilage remodeling.</p><p><b>METHODS</b>Disc displacement of right joints was performed in 36 of 78 rabbits under investigation. The animals were sacrificed at 4 days and 1, 2, 4, 8 and 12 weeks after surgery, respectively. The right joints of these animals were harvested and processed for the examination of mRNA expression of uPA and PAI-1 in articular cartilage using in situ hybridization techniques.</p><p><b>RESULTS</b>The expression of uPA and PAI-1 was co-expressed weakly in the chondrocytes from transitive zone to hypertrophic zone and mineralized zone, while no hybridizing signals were shown in proliferative zone and superficial zone in control rabbits. The most striking was the up-regulation of uPA and PAI-1 mRNA in 4-day rabbits postoperatively at the onset of cartilage degeneration. The strongest hybridizing signals for uPA and PAI-1 were seen in 2-week rabbits postoperatively. After 2 weeks, the expression of uPA and PAI-1 began to decrease and reached nearly normal level at 12 weeks.</p><p><b>CONCLUSIONS</b>The expression of the uPA/PAI-1 system coincides with the pathological changes in condylar cartilage after DD. The uPA/PAI-1 system may be one of the essential mediators in articular cartilage remodeling.</p>

Expression related to vascular endothelial growth factor C and induced nitride oxide synthesizase in lymph node micrometastasis of oral squamous cell carcinoma / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the relationship of vascular endothelial growth factor C (VEGF-C) and induced nitride oxide synthesizase (iNOS) expression in lymph node micrometastasis of oral squamous cell carcinoma.</p><p><b>METHODS</b>Samples were obtained from 47 cases of oral squamous cell carcinoma and 15 cases with normal oral mucosa, VEGF-C and iNOS mRNA expression were detected by RT-PCR method. Lymph node micrometastasis of 10 normal lymph nodes and 355 lymph nodes from 47 cases of oral squamous cell carcinoma was detected with immunohistochemical reaction in cytokeratin antibody.</p><p><b>RESULTS</b>The percentages in tumors with higher expression were 57.4% for VEGF-C, 68.1% for iNOS (P < 0.05). They were significantly higher than that of normal groups. Significant positive relationship was found between VEGF-C and iNOS (P < 0.01). The positive rate of cytokeratin (CK) was 48.9%. Significant positive relationship was found between VEGF-C and CK, iNOS and CK (P < 0.01). The expression rates of CK in positive group of VEGF-C and iNOS were 63.0%, 65.6% respectively, and were significant higher than negative groups.</p><p><b>CONCLUSION</b>Expression of VEGF-C and iNOS in lymph node micrometastasis of oral squamous cell carcinoma is significant related.</p>

Changes of taste bud and fungiform papillae after 60Co radiation in rat / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the morphological changes and the regenerating ability of the fungiform papillae and taste buds after 60Co radiation with clinical doses in rats.</p><p><b>METHODS</b>The heads, faces and necks of 30 SD rats were radiated with a large dose and one time of 60Co in the clinical radiation. The general living condition and the number and shape of the fungiform papillae and taste buds of the tongues were observed after the radiation in rats.</p><p><b>RESULTS</b>In the group of 60Co radiation, the animals had wilting, decreasing appetite, losing weight. The heads, faces and necks of animals appeared redness, peeling of hair, increasing of secretions in 5 days after the 60Co radiation. The changes reached the summit in 10 days and the general living condition of the animals recovered in 60 days. The fungiform papillae and taste buds of the animals appeared degeneration, atrophy and collapsing in 5 days after the 60Co radiation. The injuries reached the summit in 10-20 days and the fungiform papillae and taste buds regenerated partially, and the some atrophied fungiform papillae and taste buds were not regenerated in 60 days.</p><p><b>CONCLUSION</b>The damage to fungiform papillae and taste buds of tongue following the 60Co radiation with the clinical doses was very serious. The damaged fungiform papillae and taste buds can regenerate partially, but not completely.</p>

Gene expression changes of cartilage matrix of condylar cartilage with anterior disc displacement / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the gene expression changes in extracellular matrix of condylar cartilage following disc anterior displacement of rabbit TMJ.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>Collagen 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.</p><p><b>CONCLUSION</b>Anterior disc displacement leads to alteration of extracellurar matrix gene expression in the condylar chondrocyte, which means the start of remodeling.</p>

The relationship between lymphangiogenesis and cervical lymph node micrometastasis in oral squamous cell carcinoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To probe the relationship between lymphangiogenesis and cervical lymph node micrometastasis in oral squamous cell carcinoma.</p><p><b>METHODS</b>The microlymphatic vessel density was detected with enzyme histo-chemical method in 47 cases of oral squamous cell carcinoma and 10 cases of normal oral mucosa; 355 lymphnodes were detected with immunohistochemically using monoantibody AE3.</p><p><b>RESULTS</b>The mean MLVD was 14.04 +/- 6.92 in tumor group, or 5.48 +/- 2.62 in normal group. The difference was (P < 0.001). The percentage of tumor with expression CK was 48.9%. The mean MLVD was 16.94 +/- 5.43 in CK positive group, or 11.26 +/- 5.00 in CK negative group, There was difference significant (P < 0.001).</p><p><b>CONCLUSIONS</b>Lymphangiogenesis plays a key role in cervical lymph node micrometastasis of oral squamous cell carcinoma.</p>

Disc-like changes and type II collagen mRNA expression in the bilaminar zone of rabbit temporomandibular joint following disc displacement / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the adaptive alteration in bilaminar zone of rabbits' temporomandibular joint following disc displacement.</p><p><b>METHODS</b>Twenty-six Japanese white rabbits were used in this study. Among these rabbits,6 were used as controls. The right discs of other 20 rabbits were displaced anteriorly by operation. Four of these rabbits were killedatn 1, 2, 4, 6 and 8 weeks respectively after surgery. The TMJS were studied by HE staining, Alcin bluen staining and in situ detection of type II collagen mRNA expression.</p><p><b>RESULTS</b>There appeared cartilage metaplasia after one week following disc displacement. Typical chondrocytes could be found in the bilaminar zone. The new chondrocytes expressed type II collagen.</p><p><b>CONCLUSIONS</b>The bilaminar zone of TMJ will be remodeled following disc displacement and become a disc-like tissue to function as a disc.</p>