An in-vivo Intraoral Defect Model for Assessing the Use of P11-4 Self-Assembling Peptide in Periodontal Regeneration.

Periodontal disease is one of the most common diseases worldwide. It has a significant impact on oral health and subsequently the individual's quality of life. However, optimal regeneration of periodontal tissues, using current treatments, has yet to be achieved. Peptide self-assembly has provided a step-change in nanobiotechnology and regenerative medicine fields. Our aim was to investigate the effects of a self-assembling peptide (SAP; P11-4) on periodontal regeneration in a preclinical model. Twenty-six bilateral maxillary critical-sized periodontal defects were created surgically in 13 rats. Defects on one side of the mouth were filled with P11-4 hydrogel; the contra-lateral defect was untreated (control). Rats were sacrificed immediately post-surgery (time 0) and after 2 and 4 weeks. Retrieved maxillae were processed for histological, immunohistochemical, and histomorphometric assessments. The results of histological analysis showed greater organization of periodontal fibers in defects treated with P11-4, at both time points, when compared to untreated defects. Histomorphometry showed that treated defects had both a significant increase in functional periodontal ligament length and a reduction in epithelial down growth after 4 weeks. At 2 weeks, treated defects showed a significant increase in expression of osteocalcin and osteoprotegerin as judged by immunohistochemistry. Also, a significantly higher osteoprotegerin/RANKL ratio was shown in treated defects. In conclusion, the results demonstrated enhanced regeneration of periodontal tissues when SAP P11-4 was used to fill periodontal defects in rats. The findings of this study suggest that SAP P11-4 is a promising novel candidate for periodontal regenerative therapy. Further investigations are required for optimization before clinical use.

Efficacy of azithromycin and metronidazole combined therapy on rats' gingival overgrowth induced by cyclosporine-A: An experimental animal study.

AIMS: To evaluate the therapeutic efficacy of azithromycin (azm) and/or metronidazole (mtz) on the histopathological features of rats' gingival overgrowth (GO) induced by cyclosporine-A (CsA) in an animal model. METHODS: Ninety male albino rats were divided randomly into six equal groups. The rats of group I received corn oil via gastric feeding for 7 weeks. Group II rats were administered CsA for the same period. Groups III, IV, and V rats received CsA for 6 weeks and simultaneously in the 7th week received a monotherapy of placebo gel, azm suspension, mtz gel, respectively. Group VI rats were handled as groups III, IV, and V and instead received a combined therapy of azm suspension, and mtz gel. Rats were euthanized at the end of the experiment and routine tissue processing was carried out. The obtained specimens were stained with H&E, TGF-ß, MMP-1, and IL-6 antibodies. RESULTS: One-way MANOVA test for TGF-ß, MMP-1, and IL-6 revealed an overall significant difference between the different groups (P = 0.000). LSD post hoc test for multiple comparisons of TGF-ß revealed nonsignificant difference between groups I and VI and between groups IV and V. Nonsignificant difference was found between groups II and III considering the amount of MMP-1 immune expression. In addition, nonsignificant difference was found between groups V and VI regarding the amount of immune expression for IL-6. CONCLUSION: Combined therapy of azm suspension and mtz gel significantly improved the histopathological features of CsA-induced GO better than a monotherapy of azm suspension or mtz gel.

In vivo association of immunophenotyped macrophages expressing CD163 with PDGF-B in gingival overgrowth-induced by three different categories of medications.

AIMS: This study was carried out to identify and outline the degree of relationship between immunophenotyped macrophages expressing CD163 and PDGF-B in cyclosporine-A, phenytoin, and nifedipine-induced gingival overgrowth. METHODS: Eighty adult male albino rats were selected and divided into four equal groups. Group I received no treatment. Rats of groups II, III, and IV were administered cyclosporine-A, phenytoin, and nifedipine, respectively. Routine tissue processing was carried out for staining with CD163 and PDGF-B. The results of this study were analyzed statistically. RESULTS: Group I exhibited score 0 gingival overgrowth while group II yielded score 3 with blunt and bulbous gingival crests. Rats of group III showed score 2 with knife edge and group IV revealed less pronounced gingival overgrowth and mostly the gingival crest was knife edge. Group II had the highest mean value for CD163 while group I showed the lowest value. In addition, group II had the highest mean value for PDGF-B while group I showed the lowest value. Statistically, there was an overall significant difference between the studied groups as well as between each two groups. CONCLUSION: Strong association exists between immunophenotyped macrophages expressing CD163 and PDGF-B in GO induced by these medications. In addition, CD163 and PDGF-B upregulated in cyclosporine-A-induced GO compared to phenytoin and nifedipine medications.