Introduction:Chitosan is a biodegradable, naturally occurring polymer with recently used as a scaffold material in tissue engineering. To maximize the biocompatibility and bioactivity of Chitosan, nanohydroxyapatite has been incorporated into chitosan scaffolds.Aim: This study aimed to investigate bone healing after placing CS/nHA scaffold in bone regeneration of extracted socket in rabbits with induced osteoporosis. Materials and Methods:We used 40 New Zealand white rabbits randomly divided into 4 groups: group A (-ve Control), group B (+ve Control with CS/nHA scaffold), group C (osteoporosis with CS/nHA scaffold), and group D (osteoporosis without CS/nHA scaffold). After induction of osteoporosis and surgical extraction, the rabbits were euthanized at 2 and 6 weeks. The effect of CS/ nHA was evaluated histologically and immunohistochemically using ALP, OP, and BMP-2 markers.Results: Our results showed enhanced bone trabeculae in group B and C comparable with the group A. However, thin bone trabeculae with irregular bone surfaces were seen in group D. Our histological findings were confirmed by the newly formed bone surface area histomorphometry, besides ALP, BMP-2, and OP immunoexpression showing a sustained significant increase in group B and C compared with group D across both intervals. Conclusion:The histology and immunoexpression of bone healing markers was positively affected by the placement of CS/nHA scaffolds under osteoporotic conditions. These results may indicate that CS/nHA scaffolds could be used to augment bone healing and improve the quality of newly formed bone after extraction in patients with osteoporosis required for future surgical procedures such as dental implantation.

Background This study aimed to investigate the influence of hyperbaric oxygen therapy on mandibular critical-sized defect regeneration in rats with experimentally induced type I diabetes mellitus. Restoration of large osseous defects in an impaired osteogenic condition such as diabetes mellitus is a challenging task in clinical practice. Therefore, investigating adjunctive therapies to accelerate the regeneration of such defects is crucial. Materials and methods Sixteen albino rats were divided into two groups (n = 8/group). To induce diabetes mellitus, a single streptozotocin dosage was injected. Critical-sized defects were created in the right posterior mandibles and filled with beta-tricalcium phosphate graft. The study group was subjected to 90-min sessions of hyperbaric oxygen at 2.4 ATA, for 5 consecutive days per week. Euthanasia was carried out after 3 weeks of therapy. Bone regeneration was examined histologically and histomorphometrically. Angiogenesis was assessed by immunohistochemistry against vascular endothelial progenitor cell marker (CD34) and the microvessel density was calculated. Results Exposure of diabetic animals to hyperbaric oxygen resulted in superior bone regeneration and increased endothelial cell proliferation, which were revealed histologically and immunohistochemically, respectively. These results were confirmed by histomorphometric analysis which disclosed a higher percentage of new bone surface area and microvessel density in the study group. Conclusions Hyperbaric oxygen has a beneficial effect on bone regenerative capacity, qualitatively and quantitively, as well as the ability to stimulate angiogenesis.

INTRODUCTION:Significant development has been achieved with bioceramics and biopolymer scaffolds in the construction of artificial bone. In the present study, Chitosan-nanohydroxyapatite (CS/nHA) scaffolds have been developed as bone graft substitutes in rabbits with induced osteoporosis. OBJECTIVES: To evaluate the effect of Chitosan-nanohydroxyapatite (CS/nHA) scaffold in bone tissue regeneration of extracted socket in rabbits with induced osteoporosis; using Scanning Electron Microscope and Energy Dispersive x-ray analysis [EDXA]. MATERIALS AND METHODS: Twenty NewZealand white female rabbits were randomly divided into 2 equal groups; group A (osteoporosis) with no graft material, and group B (osteoporosis with CS/nHA). After the experimental period the animals were sacrificed at 2 & 4 weeks. The effect of CS/Nha was evaluated using Scanning Electron Microscope and Energy Dispersed x-ray analysis [EDXA]. The data obtained was tabulated and subjected to statistical analysis. RESULTS: Scanning Electron Microscopic results revealed more trabecular bone thickness with regular bone surface, and uniform osteocyte lacunae in the group B (osteoporosis with CS/nHA) than group A (osteoporosis), and these results were proved by EDXA which showed more Ca and P ratio in the group B than group A. CONCLUSIONS: CS/nHA scaffold is considered an effective hard tissue engineering material with sufficient interconnected porosity and mechanical strength to allow cell adhesion, migration, growth and proliferation resulting in good integration with surrounding tissues, and rapid bone healing, thus it might be used in osteoporotic condition.

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Introduction:Herbal extracts have shown protective efficacy on organs toxicity. Carbontetra chloride (CCl4) induce the production of free radical. Silymarin has potent cytoprotecting antioxidant effects.Aim: was to investigate the role of Silymarin in lowering the cytotoxic effect of CCL4 on the salivary glands of rats.Materials and methods: Thirty-six rats were randomly assigned into three equal groups: Group I (Control) received (1 ml) saline orally for 21 days. Group II: (CCl4) received saline orally for 15 days followed by CCl4 (1.5 mg/kg, i.p.) twice per week until day 21. Group III: (Silymarin+CCl4) received silymarin (25 mg/kg, oral) orally for 15 days followed by CCl4 (1.5 mg/kg, i.p.) till day 21. Rats were euthanized after 21 days; after dissecting the salivary glands, they were prepared for routine H&E and immunohistochemical evaluation for caspase-3. Lastly, the antioxidant marker Reduced glutathione (GSH), the oxidative stress markers Malondialdehyde (MDA), and Nitric Oxide (NO) were assessed. Results:The histological results revealed acinar and ductal apoptotic changes in the CCl4 group. In group III, the degenerative changes induced by CCl4 were reduced. CCl4 in group II significantly increased NO and MDA levels as well as decreased GSH levels. Silymarin significantly decreased NO and MDA, while increased GSH compared to group II. Caspase-3 immunoexpression was lower in Group III compared to CCl4 group.Conclusions: Silymarin has a protective antioxidant activity on the salivary glands that reduces the toxic effects produced by CCl4.