Effect of cyclosporine-A on orthodontic tooth movement in rats

OBJECTIVE

The objective of this study is to examine the effect of cyclosporine-A (CsA) on the rate of orthodontic tooth movement in rats.

SETTING AND SAMPLE POPULATION

This is a randomized controlled trial with a split-mouth design in Sprague-Dawley rats.

MATERIAL AND METHODS

Eighteen rats, divided at random in two groups, were fed with 8 mg/kg CsA (experiment) or mineral oil (control) daily after initial healing of bilateral maxillary second molar removal. All rats received orthodontic coil springs (10 cN) secured to the maxillary incisors and first molars at the rights side, while no springs were placed at the left. Distances between first and third molars were measured on days 0, 3, 6, and 12. After sacrificing on day 12, the alveolar ridges of the maxillae were sectioned and blood samples were collected for serum tartrate-resistant acid phosphatase (TRAP)-5b level detection and for histology, respectively.

RESULTS

Significantly larger changes in intermolar distances were found after orthodontic force application in the CsA group at days 3 and 12 when compared with the control group. The inter-radicular dental alveolus of CSA-fed rats was osteopenic. Significantly increased TRAP-5b serum level was noted in the CsA group when compared with the control group.

CONCLUSIONS

We suggest that CsA enhanced the rate of orthodontic tooth movement. The osteopenia and the increased osteoclastic activity could be the underlying factors.

Dynamic recording of irrigating fluid distribution in root canals using thermal image analysis

AIM

To investigate the influence of the size and the depth of insertion of irrigating needles, and the diameter of the master apical file on flow distribution during fluid irrigation in root canals.

METHODOLOGY

Stepback canal instrumentation was employed on seven extracted human single canal teeth. The size of the master apical files ranged from sizes 25, 30, 35, 40, 45, 50 to size 80 within the seven teeth, respectively. A thermal imaging system (ThermaCAM; National Instruments Co., Austin, TX, USA) was used to record the dynamic fluid distribution following root canal preparation. The dynamic fluid distribution was analysed during irrigation by insertion of different irrigating needle tips (23, 25 and 27 gauge) at various depths (3, 6 and 9 mm) from the root apex. The whole process of irrigation was recorded by a video camera and analysed by two observers separately. The success of the irrigation process was defined when the irrigant was able to flow into to the apical region immediately after injection.

RESULTS

The aqueous irrigant was flushed into the apical region when a size 27 gauge irrigating needle was placed into a size 30 canal at a point 3 mm from the apical stop. When the same needle tip was placed 6 mm from the root canal apex, successful irrigation was achieved only in the canals prepared to size 50 or larger. When a size 25 gauge irrigating needle was placed 3 mm from the working length, the canal size had to be no <45 to allow for successful irrigation. When a size 23 gauge needle was placed at the same position, the canal needed to be prepared to size 50 to allow thorough irrigation of the apex. At 9 mm from the apical stop, none of the irrigating needles could achieve successful irrigation of any canal size.

CONCLUSION

The flow distribution of root canal irrigation can be affected adversely by large diameter irrigating needles, by greater distances between the needle tip and the apical stop, and by narrow root canals.

Releasing growth factors from activated human platelets after chitosan stimulation: a possible bio-material for platelet-rich plasma preparation

INTRODUCTION

Thrombin is commonly used for activating the platelets and releasing the growth factors on the application of platelet-rich plasma (PRP). We have previously reported that chitosan can enhance rabbit platelet aggregation. In this study, the effects of chitosan on the subsequent growth factors release after human platelets activation were examined to evaluate the possibility of chitosan being used as a substitute for thrombin during PRP preparation.

MATERIAL AND METHODS

Human platelet activation was determined by aggregation, adhesion and alpha-granule membrane glycoprotein expression. Platelet aggregation was measured by the turbidimetric method, the adhesion was directly examined on chitosan-coated glass plates under light microscope and scanning electron microscope (SEM), and the alpha-granule membrane glycoprotein was detected by fluorescent isothiocyanate (FITC)-conjugated anti-CD61 antibody through flow cytometry. The subsequent epidermal growth factor (EGF), platelet-derived growth factor (PDGF)-AB and transforming growth factor (TGF)-beta1 release from platelets were assayed by ELISA after mixing with chitosan.

RESULTS

The enhancing effects on the platelet adhesion and the aggregation from chitosan were observed. Under both microscopes, the adhesive platelets on the chitosan-coated plates were not only greater in number but also earlier in activation than those on the control plates. With flow cytometry, increased glycoprotein IIIa expression in platelets was detected after chitosan treatment. Greater concentrations of growth factors were measured from PRP after chitosan treatment than after the solvent treatment.

CONCLUSION

Because of the observations of growth factors releasing from activated human platelets after chitosan stimulation, we suggest that chitosan may be an appropriate substitute for thrombin in PRP preparation.

Cyclosporin-induced downregulation of the expression of E-cadherin during proliferation of edentulous gingival epithelium in rats

BACKGROUND

To examine the role of E-cadherin in epithelial hyperplasia of cyclosporin A (CsA)-induced gingival enlargement, mRNA and protein levels of E-cadherin, beta-catenin, proliferating cell nuclear antigen (PCNA), and Cyclin D1 were examined in the edentulous gingiva of rats following CsA treatment.

METHODS

Three weeks after the extraction of all maxillary molars, 20 male Sprague-Dawley rats were assigned to a CsA-fed group (30 mg/kg daily) or a control group. Five rats per group were sacrificed at weeks 1 and 4. Edentulous ridge specimens were taken, and the expression levels of E-cadherin, beta-catenin, Cyclin D1, and PCNA mRNAs were estimated by reverse transcription-polymerase chain reaction (RT-PCR). Tissue specimens of the week 4 groups were examined using immunohistochemical (IHC) staining for proteins.

RESULTS

The mRNA expression of E-cadherin was significantly weaker in the CsA-treated group than the control group at both times. Using IHC staining, a weaker level of membrane-bonded E-cadherin was also observed in the gingival epithelial cells in the CsA group than in controls. By contrast, significantly stronger beta-catenin and Cyclin D1 mRNA expressions and protein levels were found in CsA-treated rats than controls by RT-PCR and immunohistochemistry at week 4, whereas PCNA production was stronger at both times.

CONCLUSIONS

CsA treatment reduced the production of E-cadherin but increased the production of beta-catenin, Cyclin D1, and PCNA. Thus, CsA may downregulate E-cadherin gene expression, leading to the epithelial cell proliferation of gingival overgrowth.

Upregulation of the Expression of Epidermal Growth Factor and Its Receptor in Gingiva Upon Cyclosporin A Treatment

BACKGROUND

To understand the roles of epidermal growth factor (EGF) and EGF receptor (EGF-R) in cyclosporin A (CsA)-induced gingival overgrowth, expression of EGF and EGF-R upon CsA treatment was examined in an oral epidermoid carcinoma cell line of humans (OECM-1) and in edentulous gingiva of rats.

METHODS

In vitro study: after CsA treatment, OECM-1 cells were harvested to evaluate their mRNA and protein expression of EGF and EGF-R with reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and immunocytochemistry (ICC). In vivo study: 3 weeks after extraction of all maxillary molars, 20 male Sprague-Dawley rats were assigned to a CsA group (30 mg/kg, fed daily) and a control group. Five rats per group were sacrificed at weeks 1 and 4. Edentulous ridge specimens were obtained for evaluating their mRNAs and protein expression with RT-PCR, real-time RT-PCR, and immunohistochemistry (IHC). In both in vitro and in vivo experiments, the proliferating potential of epithelial cells was examined by the presence of proliferating cell nuclear antigen (PCNA).

RESULTS

In vitro: dose-dependently increased mRNA expression of EGF and EGF-R in OECM-1 cells was noted after CsA treatment. Protein expressions of EGF and EGF-R were higher in OECM-1 with CsA treatment than without CsA. In vivo: higher mRNA and protein expressions of EGF and EGF-R were also observed in the gingival tissues of CsA-treated rats. In both in vitro and in vivo experiments, greater PCNA expression after CsA treatment was demonstrated.

CONCLUSIONS

Higher expression of EGF and EGF-R upon CsA therapy was observed in OECM-1 epithelial cells of humans and in edentulous gingiva of rats. We suggest that CsA could upregulate gene and protein expression of EGF and EGF-R, and the upregulation may play a role in gingival overgrowth.

Upregulation of Transforming Growth Factor-β1 and Vascular Endothelial Growth Factor Gene and Protein Expression in Cyclosporin-Induced Overgrown Edentulous Gingiva in Rats

BACKGROUND

To examine the effects of cyclosporin A (CsA) on the expression of growth factors in induced gingival overgrowth with limited contributing factors arising from local inflammation caused by bacterial plaque, this study of gingival overgrowth was designed on the edentulous ridge of rats.

METHODS

After a 3-week healing period following maxillary molar extractions, 16 five-week-old male Sprague-Dawley rats were assigned to CsA and control groups. Animals in the CsA group were fed 30 mg/kg CsA daily, whereas the control rats received a mineral oil vehicle instead. After 4 weeks, all animals were sacrificed, and the morphology of edentulous ridges was recorded by dental impression. The gingivae on the left-hand side were dissected and stored for mRNA analysis, whereas the gingivae on the right-hand side were fixed in 4% paraformaldehyde for immunohistochemistry (IHC) analysis of transforming growth factor-beta1 (TGF-beta1), platelet-derived growth factor beta (PDGF-beta), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF).

RESULTS

The edentulous gingivae were enlarged and the body weights were reduced in the CsA-treated animals compared to controls. The mRNA expressions of TGF-beta1, IGF-1, and VEGF were higher in the gingivae of the CsA group than in the control group. In addition, a greater mRNA expression (7.21-fold) of VEGF was demonstrated in the CsA group than in the control group by real-time polymerase chain reaction (PCR). The percentages of cells staining positive for TGF-beta1 and VEGF were significantly greater in the CsA rats than in the control rats.

CONCLUSIONS

Greater mRNA expression and positive staining for TGF-beta1 and VEGF were observed in the edentulous gingivae of rats that received CsA. Therefore, CsA may upregulate TGF-beta1 and VEGF gene expression and protein secretion in CsA-induced gingival overgrowth.

Effect of Cyclosporin A on the Expression of Inducible Nitric Oxide Synthase in the Gingiva of Rats

BACKGROUND

The role of nitric oxide (NO) in the pathogenesis of cyclosporin A (CsA)-induced gingival overgrowth is still unknown. The purpose of this study was to evaluate the effect of CsA on the expression of nitric oxide synthases (NOS) in the gingival tissue of rats.

METHODS

Thirty male Sprague-Dawley rats were randomly assigned to a control and two test groups. Rats in each group received CsA (0, 10, or 30 mg/kg) daily by gastric feeding for 4 weeks. The plasma NO and the NOS enzyme activities were assayed at week 4 in the blood samples and in the gingiva and lung tissue specimens, respectively. The distribution of inducible nitric oxide synthase (iNOS) was further evaluated in tissues obtained from the gingiva and lung at the end of weeks 1 and 4 by immunohistochemistry.

RESULTS

In the CsA-treated animals, increased levels of plasma nitrites/nitrates were measured in comparison to those in control rats. Significantly greater iNOS enzyme activities were detected in lung and gingival tissues obtained from CsA-treated animals than from control animals. In addition, cells positively staining for iNOS were clearly observed in both gingival and lung tissues obtained from the CsA-treated animals by immunohistochemistry, whereas a few stained cells were found in those from the control group. The quantity of cells positively stained for iNOS was greater in tissue from week 4 than week 1.

CONCLUSIONS

The effect of CsA on gingival iNOS expression was evaluated in rats for 4 weeks. A greater iNOS expression in the gingiva was observed after CsA therapy by both enzyme activities and immunohistochemica staining. Therefore, we suggest that CsA can increase gingival iNOS expression, which may play an important role in cyclosporin-induced gingival overgrowth.

Effect of Cyclosporin A on the Mineral Apposition Rate of Cementum and Dentin in Growing Rats

BACKGROUND

Since there is no direct information to verify whether cyclosporin A (CsA) can affect the mineralization of dental hard tissue, the formation of dentin and cementum in growing rats was recorded by labeling the mineral phase of these tissues with fluorochrome marker in this study.

METHODS

After the extraction of the right maxillary molars, 30 male 3-week-old Sprague-Dawley rats were assigned to two groups. Following a 2-week healing period, the experimental rats received 30 mg/kg CsA daily for 7 weeks, while the control rats received only mineral oil. The fluorescent markers, calcein and alizarin red, were given on alternate weeks for 7 weeks. At the end of study, the mandibles were obtained and undemineralized sections were processed. Serial sections, 8 microm thick, were cut for the entire distal roots of the first molars. Five central sections were selected to determine the mineral apposition of cellular cementum and dentin at the apex and middle of root, respectively.

RESULTS

The apposition rates of apical cellular cementum were significantly influenced by CsA therapy, occlusal function, and observation duration. However, the dentin apposition rates were significantly influenced by the observation intervals only.

CONCLUSIONS

In this study, CsA therapy and occlusal function significantly influenced the apposition rates of apical cementum, but not the rates of mid-root dentin. Our hypothesis that CsA can induce oral hard tissue alterations, as well as gingival overgrowth, is demonstrated.

Is p16INK4A expression more useful than human papillomavirus test to determine the outcome of atypical squamous cells of undetermined significance-categorized Pap smear? A comparative analysis using abnormal cervical smears with follow-up biopsies

OBJECTIVE

To correlate high-risk human papillomavirus (HR-HPV) viral load to p16(INK4A) expression in atypical squamous cells of undetermined significance (ASCUS)-categorized Pap smears with follow-up biopsies in order to elucidate their relationships in gynecological pathology.

METHODS

We studied 66 ASCUS-categorized Pap smears with subsequent follow-up biopsies. HR-HPV viral load was determined by Hybrid Capture II assay from the cervical swab in each ASCUS-diagnosed Pap smear. Both smears and biopsies were immunostained with a primary anti-p16 antibody, clone E6H4, and we analyzed the correlations between HR-HPV viral load in each ASCUS-diagnosed Pap smear and p16 expression of smears with follow-up biopsies.

RESULTS

Correlation analyses of the corresponding histological diagnoses from 66 ASCUS-diagnosed Pap smears revealed that 21 (32%) cases had only reactive changes and 45 cases showed cervical intraepithelial neoplasia including LSIL (24 cases, 36%) and HSIL or higher (21 cases, 32%). Tests for HR-HPV viral load revealed 17 (26%) negative cases and 49 (74%) positive cases. Immunostaining showed that 26 cases (39%) were negative and 40 (61%) were positive for p16 expression. Comparative analysis of these two tests indicated consistencies as well as discrepancies. They showed significant differences (P < 0.001) between negative p16 expressions of Pap smears with the presence of reactive lesions in follow-up biopsies and HR-HPV viral load. However, no significant difference (P = 0.739 and 0.606) between p16 expression of Pap smears with the presence of LSIL, HSIL or higher in follow-up biopsies and high HR-HPV viral load was found. In addition, there were significant differences (P < 0.001) in specificity and positive predictive value, but no significant differences were found in sensitivity (P = 0.606) and negative predictive value (P = 0.062) between p16 immunostaining and HR-HPV viral load.

CONCLUSION

The results indicate that there is a close association between weak or strong p16 expressions in ASCUS-categorized smears with the presence of SILs in follow-up biopsies and positive HR-HPV viral loads. Conversely, there is also a clear association between the lack of p16 expression and the absence of significant lesions in follow-up biopsies, but this is not consistent with a negative HR-HPV viral load. It is concluded that p16 expression is an indicator of pathogenic activity of HR-HPV, which is an objective biomarker for clarification of ASCUS-categorized Pap smears in gynecological cytopathology. Furthermore, through comparative analysis, directly visualized p16 immunostaining on smears appears to be a more effective method than HR-HPV viral load for the detection of reactive changes and LSILs from ASCUS-categorized Pap smears.

Periodontal status in post-menopausal osteoporosis: a preliminary clinical study in Taiwanese women

BACKGROUND

Osteoporosis and periodontitis are common diseases affecting post-menopausal women; however, the exact relationship between the diseases is still uncertain. The purposes of this study were to examine the periodontal status in a group of type I post-menopausal women with and without osteoporosis and to elucidate the possible role of the osteoporosis in the pathogenesis of periodontal disease.

METHODS

Thirty-four patients (18 in the osteoporotic and 16 in the non-osteoporotic group) were selected from 329 post-menopausal Taiwanese women who had completed radiographic measurements of spinal bone mineral density and received full-mouth periodontal examination. Periodontal measurements, including O'Leary plaque index, probing depths, clinical attachment level, and gingival recession, on 6 sites of each tooth of full mouth were examined and recorded by 1 examiner.

RESULTS

Significantly greater probing depth was noted at the interproximal, but not at the facio-lingual, osteoporotic sites if compared to those non-osteoporotic sites. The depth was also significantly influenced by the examining factors of plaque accumulation, tooth location, and jaws. By individual jaw, increased attachment loss accompanied by greater probing depth and gingival recession was found at the osteoporotic sites on mandible if compared to non-osteoporotic sites. On maxilla, however, less gingival recession and attachment loss were observed at the osteoporotic sites.

CONCLUSIONS

In the present study, increased attachment loss accompanied by greater probing depth and gingival recession was found at the osteoporotic sites on mandible. However, the parameters were also influenced by the examining factors of plaque accumulation, tooth location, and jaws. Therefore, we suggest that post-menopausal osteoporosis may play a role in the pathogenesis of periodontal disease, especially on the mandible, although the etiology of periodontal disease is still multi-factorial.