Osteoprotective Effect of Enamel Matrix Derivatives on the Regeneration of Mandibular Defects in Experimentally Glucocorticoid-Induced Osteoporosis.

PURPOSE: Osteoporosis is a progressive systematic skeletal illness characterized by low bone mineral density and susceptibility to fracture caused by bone resorption. Aim of the Study. This study intended to evaluate the possible role of emdogain in combination with calcitonin on the healing of surgically induced mandibular defects performed on osteoporotic rats. MATERIALS AND METHODS: Forty healthy female white albino rats were included in this study and divided into four groups. In group I (negative control), 10 rats received a vehicle injection after which a unilateral mandibular defect was created in each rat of all groups. Three groups were subjected to induction of osteoporosis by subcutaneous injection of 0.1 mg/kg/day dexamethasone for 60 days. In group II, rats were kept without treatment. In group III, rats were treated with daily intramuscular injection of 2.5 IU/kg of synthetic salmon calcitonin. In group IV, rats were handled as group III, and the created cavity was filled with emdogain. Rats were euthanized at 2nd and 4th week postsurgically. Hematoxylin and eosin, Masson's trichrome, NF-κB (nuclear factor of activated B cells), and immunohistochemical stains were used, followed by statistical analysis. RESULTS: Group I showed normal stages of bone defects healing. Group II revealed the formation of granulation tissue with dilated blood vessels, while groups III and IV showed enhanced bone healing and proper collagen fibers. The percentage area of newly formed collagen fibers was significantly higher in group IV at 2nd week (13.96 ± 0.020%) and 4th week (16.95 ± 0.024%) than in group II (8.75 ± 0.015% and 10.29 ± 0.015%, respectively) and group III (12.93 ± 0.015% and 14.61 ± 0.021%, respectively), but was lower than that in group I (15.75 ± 0.015% and 17.49 ± 0.015%, respectively). CONCLUSION: The local application of emdogain combined with systemically injected calcitonin improves bone healing in surgically induced bone defects in osteoporotic rats.

Dental pulp stem cells stimulate neuronal differentiation of PC12 cells.

Dental pulp stem cells (DPSCs) secrete neurotrophic factors which may play an important therapeutic role in neural development, maintenance and repair. To test this hypothesis, DPSCs-conditioned medium (DPSCs-CM) was collected from 72 hours serum-free DPSCs cultures. The impact of DPSCs-derived factors on PC12 survival, growth, migration and differentiation was investigated. PC12 cells were treated with nerve growth factor (NGF), DPSCs-CM or co-cultured with DPSCs using Transwell inserts for 8 days. The number of surviving cells with neurite outgrowths and the length of neurites were measured by image analysis. Immunocytochemical staining was used to evaluate the expression of neuronal markers NeuN, microtubule associated protein 2 (MAP-2) and cytoskeletal marker ßIII-tubulin. Gene expression levels of axonal growth-associated protein 43 and synaptic protein Synapsin-I, NeuN, MAP-2 and ßIII-tubulin were analysed by quantitative polymerase chain reaction (qRT-PCR). DPSCs-CM was analysed for the neurotrophic factors (NGF, brain-derived neurotrophic factor [BDNF], neurotrophin-3, and glial cell-derived neurotrophic factor [GDNF]) by specific ELISAs. Specific neutralizing antibodies against the detected neurotrophic factors were used to study their exact role on PC12 neuronal survival and neurite outgrowth extension. DPSCs-CM significantly promoted cell survival and induced the neurite outgrowth confirmed by NeuN, MAP-2 and ßIII-tubulin immunostaining. Furthermore, DPSCs-CM was significantly more effective in stimulating PC12 neurite outgrowths than live DPSCs/PC12 co-cultures over the time studied. The morphology of induced PC12 cells in DPSCs-CM was similar to NGF positive controls; however, DPSCs-CM stimulation of cell survival was significantly higher than what was seen in NGF-treated cultures. The number of surviving PC12 cells treated with DPSCs-CM was markedly reduced by the addition of anti-GDNF, whilst PC12 neurite outgrowth was significantly attenuated by anti-NGF, anti-GDNF and anti-BDNF antibodies. These findings demonstrated that DPSCs were able to promote PC12 survival and differentiation. DPSCs-derived NGF, BDNF and GDNF were involved in the stimulatory action on neurite outgrowth, whereas GDNF also had a significant role in promoting PC12 survival. DPSCs-derived factors may be harnessed as a cell-free therapy for peripheral nerve repair. All experiments were conducted on dead animals that were not sacrificed for the purpose of the study. All the methods were carried out in accordance with Birmingham University guidelines and regulations and the ethical approval is not needed.

Comparative evaluation of pulpal repair after direct pulp capping using stem cell therapy and biodentine: An animal study.

The response of the dentin-pulp complex in rat teeth was investigated after direct capping with biodentine with or without bone marrow-derived stem cells (BMDSCs). Following mechanical exposure, pulps were randomly capped with one of the followings materials: calcium hydroxide, biodentine or 1 × 105 BMDSCs mL-1 + biodentine. Histological examination was performed by light microscopy after 1, 3 and 5 weeks. Inflammatory reaction, necrotic tissue formation and calcific bridge formation were scored. Analysis showed that compared with the effects of calcium hydroxide or biodentine, BMDSCs + biodentine substantially reduced inflammatory reaction and necrotic tissue while promoting calcified tissue formation. Therefore, the combination of biodentine and BMDSCs could potentially stimulate pulp tissue regeneration after direct pulp capping.

Neurotrophic effects of dental pulp stem cells on trigeminal neuronal cells.

Evidence indicates that dental pulp stem cells (DPSC) secrete neurotrophic factors which play an important role in neurogenesis, neural maintenance and repair. In this study we investigated the trophic potential of DPSC-derived conditioned medium (CM) to protect and regenerate isolated primary trigeminal ganglion neuronal cells (TGNC). DPSC and TGNC were harvested by enzymatic digestion from Wister-Hann rats. CM was collected from 72 h serum-free DPSC cultures and neurotrophic factors; nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and glial cell line-derived neurotrophic factor (GDNF) were analysed by specific enzyme-linked immunosorbent assays (ELISAs). Primary co-cultures of DPSC and TGNC were established to evaluate the paracrine effects of DPSC. In comparison, NGF was used to evaluate its neurotrophic and neuritogenic effect on TGNC. Immunocytochemistry was performed to detect the neuronal-markers; neuronal nuclei (NeuN), microtubule-associated protein-2 (MAP-2) and ßIII-tubulin. Quantitative real time polymerase chain reaction (qRT-PCR) was used to analyse neuronal-associated gene expression of NeuN, MAP-2, ßIII-tubulin in addition to growth-associated protein-43 (GAP-43), Synapsin-I and thermo-sensitive transient receptor potential vanilloid channel-1 (TRPV1). DPSC-CM contained significant levels of NGF, BDNF, NT-3 and GDNF. DPSC and DPSC-CM significantly enhanced TGNC survival with extensive neurite outgrowth and branching as evaluated by immunocytochemistry of neuronal markers. DPSC-CM was more effective in stimulating TGNC survival than co-cultures or NGF treated culture. In comparison to controls, DPSC-CM significantly upregulated gene expression of several neuronal markers as well as TRPV1. This study demonstrated that DPSC-derived factors promoted survival and regeneration of isolated TGNC and may be considered as cell-free therapy for TG nerve repair.

Role of bone marrow-derived mesenchymal stem cells on the parotid glands of streptozotocin induced diabetes rats.

The functional insufficiency of salivary glands constitute the common oral complaints in both type 1 and type 2 diabetes mellitus. The treatment with stem cell could decrease diabetic-induced hyposalivation and improve the quality of life for patients. OBJECTIVE: The current study designed to assess the biological outcome of systemic injection of stem cells on the parotid salivary gland in streptozotocin induced diabetic. METHODS: Twenty-four albino rats received intra-peritoneal injection of 50 mg/kg streptozotocin for induction of diabetes and were divided into two groups (n = 12): Group I (control) were kept without any manipulation, Group II received intravenous injection of 1×106 of mesenchymal stem cells of bone marrow derived for two days. All rats were sacrificed at 1, 3 weeks, then the parotid glands were isolated, fixed and processed for Heamatoxylin and Eosin examination, immunohistochemical staining for aquaporin-5. RESULTS: group I groups showed intracellular cytoplasmic vacuoles and focal loss of salivary architecture, while group II showed maintenance of gland architecture. Immunohistochemical examination of aquaporin-5 showed significant difference between the two groups. CONCLUSION: bone marrow derived stem cell treatment considers as an improved methods in prevention and treatment of diabeticinduced hyposalivation.

Biological assessment of ozone therapy on experimental oral candidiasis in immunosuppressed rats.

Immunosuppressive drugs can compromise local or general defense mechanisms and can lead to oral candidiasis. Ozone therapy has a wide range of applications in almost every field of dentistry. Its unique properties include immunostimulant, analgesic, antihypnotic, detoxicating, and antimicrobial actions. Sixty male healthy rats were immunosuppressed with dexamethasone in their drinking water one week before candida infection. The animals were divided into four equal groups. Rats of group 1 were kept without any manipulation and those of group II were given oral inoculums of C. albicans on the dorsal surface of the tongue. Group III rats were handled as group II and instead the rats were treated by daily mycostatin drops local applicator as a routine treatment. Meanwhile, group IV rats were handled as group II and instead the rats were received daily intraperitoneal injection of 1 cm3 of ozone oxygen gas mixture with concentration of ozone 70 µg/cm3. After two weeks, all rats were euthanized and tongue specimens were prepared for histological staining with Haematoxylin & Eosin and CD3 immunohistochemical staining. Histological examination revealed that treatment with ozone therapy lead to gradual decrease in lingual papillary atrophy and invasion of candida yeast. Immunohistochemical study showed significant decrease in CD3 counting. We can conclude that ozone acts as an excellent fungicidal agent also, ozone is capable of alerting the immune system.