Rat Periodontal Tissues Research Articles

Protective Effect of Pre-Radiotherapy Polyphenol and Bioflavonoid Application on Free Radical Levels in Rat Periodontal Tissue and Buccal Mucosa

Aim: This study aimed to assess the impact of therapeutic radiation on free radical levels in rat periodontal tissue and cheek mucosa and investigate the protective effect of pre-radiotherapy application of polyphenols and bioflavonoids (ENOANT®).
 Material and Method: Forty rats were divided into four groups, receiving various ENOANT® regimens before therapeutic radiation. Free radical levels were evaluated using MDA and sialic acid measurements.
 Results: The study found no significant difference in free radical formation among rats subjected to therapeutic dose radiation. Long-term ENOANT® use prior to radiotherapy led to a significant decrease in tissue free radical levels compared to the radiotherapy-only group.
 Conclusion: Pre-radiotherapy administration of ENOANT® demonstrated a protective effect against radiation-induced oxidative stress in rat periodontal tissue and buccal mucosa. These findings suggest ENOANT® as a promising intervention to enhance radiotherapy outcomes.

Proanthocyanidins Ameliorate LPS-Inhibited Osteogenesis of PDLSCs by Restoring Lysine Lactylation.

Periodontitis is a bacteria-induced inflammatory disease characterized by the progressive destruction of periodontal supporting tissues. Periodontal ligament stem cells (PDLSCs) are capable of differentiating into osteoblasts, which is an important stem cell source for endogenous periodontal tissue regeneration. Lysine lactylation (Kla) is a novel post-translational modification of proteins that is recently thought to be associated with osteogenic differentiation. Here, we found that lactylation levels are reduced both in the periodontal tissue of rats with periodontitis and lipopolysaccharide (LPS)-stimulated human PDLSCs. Proanthocyanidins were able to promote the osteogenesis of inflamed PDLSCs by restoring lactylation levels. Mechanistically, proanthocyanidins increased lactate production and restored the lactylation levels of PDLSCs, which recovered osteogenesis of inflamed PDLSCs via the Wnt/β-catenin pathway. These results provide evidence on how epigenetic regulation by pharmacological agents influence the osteogenic phenotype of stem cells and the process of periodontal tissue repair. Our current study highlights the valuable potential of natural product proanthocyanidins in the regenerative engineering of periodontal tissues.

Histological changes in the structural components of the gums in lipopolysaccharide periodontitis

Summary. Inflammatory diseases of periodontal tissues are one of the most important problems in dentistry. There is a strong connection between periodontal pathology and inflammatory diseases of the stomach. The aim of the study – to investigate pathomorphological changes in rat periodontal tissues with generalized lipopolysaccharide periodontitis associated with chronic atrophic gastritis. Мaterials and Methods. The experiments were performed on white outbred male rats weighing 160–180 g. 30 animals were used during the work. The tested animals were divided into the following groups: I – intact rats (control); II – animals with a model of generalized lipopolysaccharide periodontitis. For a morphological study of the periodontium, a fragment of the upper jaw was isolated. Histological preparations were studied using an SEOSCAN light microscope. Such classical research methods make it possible to study the structure of tissues, as well as the nature and depth of morphological changes, the sequence of development of destructive and regenerative processes. Results and Discussion. It has been established that with generalized lipopolysaccharide periodontitis, a reorganization of all structural components of the gum tissue occurs. It is manifested by changes in the epithelium of the mucous membrane of the gums, an increase in the stratum corneum, a decrease in the spinous layer, expansion of intercellular spaces, growth of lymphocytic infiltration, swelling of the connective tissue of the mucous membrane, expansion, blood filling of veins and hemocapillaries, cells of the walls of fibrous structures. Conclusions. Concomitant chronic atrophic gastritis significantly aggravates the pathomorphological picture of periodontitis induced in animals by the endotoxin of gram-negative microflora lipopolysaccharide.

Effect of Cells Derived from Periodontal Ligament Tissue on Bone Formation.

Recent reports indicate that sclerostin is secreted by periodontal ligament tissue-derived (PDL) cells during orthodontic force loading and that the secreted sclerostin contributes to bone metabolism. However, the detailed mechanism is poorly understood. The aim of this study was to determine how PDL cells affect bone formation. Rat periodontal ligament tissue was immunohistochemically stained for sclerostin. Cultured primary PDL cells, osteoblasts, and skin fibroblasts (Sfbs) isolated from rat periodontal ligament tissue, calvaria, and skin, respectively, were examined. Osteoblasts were cultured with control conditioned medium (Cont-CDM) and PDL cell culture conditioned medium (PDL-CDM) for up to 21 days. Cultured osteoblasts were then stained with alkaline phosphatase and von Kossa stain. Osteoblasts cultured in each conditioned medium were analyzed by real-time quantitative PCR for bone Gla protein (Bgp), Axin2, and Ki67 expression. PDL cells used to obtain conditioned medium were analyzed for Sost, Ectodin and Wnt1 expression and compared with expression in Sfbs. Expression of sclerostin was observed in periodontal ligament tissue by immunohistochemical staining. The formation of mineralization nodules was inhibited in PDL-CDM compared with Cont-CDM in osteoblast culture. In PDL-CDM, the expression levels of Bgp and Axin2 in osteoblasts were decreased compared with Cont-CDM. In PDL cells, expression levels of Sost and Ectodin were much higher than in Sfbs; however, expression of Wnt1 was lower in PDL cells compared with Sfbs. PDL cells secrete various proteins, including sclerostin and suppress osteogenesis in osteoblasts through the canonical Wnt pathway.

Deleterious effect of chronic high-dose ethanol intake on biomechanical bone properties and periodontal status.

To evaluate the effect of high-graduation chronic ethanol (EtOH) intake on bone and periodontal tissues of rats. Male Wistar rats (250g) were divided into two groups of n = 12 each one. EtOH (5ml of 3g/kg) was administered to the experimental group by gastric gavage twice a day for 20days and the control group received water under the same conditions. The rats were euthanized and used to perform biochemical determination in plasma and gingival tissue, and histological and biomechanical studies in the femur and mandibular tissues. Alcohol increased both TNFα (p < 0.01) and PGE2 (p < 0.05) in plasma and gingiva (p < 0.05) as compared to controls. In addition, EtOH increased the alveolar bone loss as evidenced by the increased distance between the cement enamel junction and the alveolar crest (p < 0.01), the lower % of interradicular bone expressed as bone area/total area (B.Ar/T.Ar, p < 0.05) and the larger periodontal space (p < 0.05), as compared to controls. Likewise, the mandibular microtomographic analysis in alcoholized rats revealed a lower % of interradicular bone volume/total volume (BV/TV, p < 0.05), greater trabecular separation (p < 0.05) and greater % trabecular porosity (p < 0.05) than controls. No biomechanical alteration was observed in lower jaws, while the femur of alcoholized rats presented a decrease in the structural bone properties (p < 0.001), as a systemic consequence of deterioration of the diaphyseal architecture (p < 0.01) without changes in material properties. The consumption of high doses of alcohol produces deleterious effects on periodontal tissues that could be due not only to local but also systemic effects.

Flavonoid extract from propolis alleviates periodontitis by boosting periodontium regeneration and inflammation resolution via regulating TLR4/MyD88/NF-κB and RANK/NF-κB pathway

Ethnopharmacological relevanceIn traditional Chinese medicine, propolis has been used for treating oral diseases for centuries, widely. Flavonoid extract is the main active ingredient in propolis, which has attracted extensive attention in recent years. Aim of the studyThe objective and novelty of the current study aims to identify the mechanism of total flavonoid extract of propolis (TFP) for the treatment of periodontitis, and evaluate the therapeutic effect of TFP-loaded liquid crystal hydrogel (TFP-LLC) in rats with periodontitis. MethodsIn this study, we used lipopolysaccharide-stimulated periodontal ligament stem cells (PDLSCs) to construct in vitro inflammation model, and investigated the anti-inflammatory effect of TFP by expression levels of inflammatory factors. Osteogenic differentiation was assessed using alkaline phosphatase activity and alizarin red staining. Meanwhile, the expression of toll like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor-kappa B (NF-κB), receptor activator of NF-κB (RANK) etc, were quantitated to investigate the therapeutic mechanism of TFP. Finally, we constructed TFP-LLC using a self-emulsification method and administered it to rats with periodontitis via periodontal pocket injection to evaluate the therapeutic effects. The therapeutic index, microcomputed tomography (Micro-CT), H&E staining, TRAP staining, and Masson staining were used for this evaluation. ResultsTFP reduced the expression of TLR4, MyD88, NF-κB and inflammatory factor in lipopolysaccharide-stimulated PDLSCs. Meanwhile, TFP simultaneously regulating alkaline phosphatase, RANK, runt-associated transcription factor-2 and matrix metalloproteinase production to accelerate osteogenic differentiation and collagen secretion. In addition, TFP-LLC can stably anchor to the periodontal lesion site and sustainably release TFP. After four weeks of treatment with TFP-LLC, we observed a decrease in the levels of NF-κB and interleukin-1β (IL-1β) in the periodontal tissues of rats, as well as a significant reduction in inflammation in HE staining. Similarly, Micro CT results showed that TFP-LLC could significantly inhibit alveolar bone resorption, increase bone mineral density (BMD) and reduce trabecular bone space (Tb.Sp) in rats with periodontitis. ConclusionCollectively, we have firstly verified the therapeutic effects and mechanisms of TFP in PDLSCs for periodontitis treatment. Our results indicate that TFP perform anti-inflammatory and tissue repair activities through TLR4/MyD88/NF-κB and RANK/NF-κB pathways in PDLSCs. Meanwhile, for the first time, we employed LLC delivery system to load TFP for periodontitis treatment. The results showed that TFP-LLC could be effectively retained in the periodontal pocket and exerted a crucial role in inflammation resolution and periodontal tissue regeneration.

Evaluated periodontal tissues and oxidative stress in rats with neuropathic pain-like behavior.

Oxidative stress has a critical effect on both persistent pain states and periodontal disease. Voltage-gated sodium NaV1.7 (SCN9A), and transient receptor potential ankyrin 1 (TRPA1) are pain genes. The goal of this study was to investigate oxidative stress markers, periodontal status, SCN9A, and TRPA1 channel expression in periodontal tissues of rats with paclitaxel-induced neuropathic pain-like behavior (NPLB). Totally 16 male Sprague Dawley rats were used: control (n = 8) and paclitaxel-induced pain (PTX) (n = 8). The alveolar bone loss and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels were analyzed histometrically and immunohistochemically. Gingival superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities (spectrophotometric assay) were measured. The relative TRPA1 and SCN9A genes expression levels were evaluated using quantitative real-time PCR (qPCR) in the tissues of gingiva and brain. The PTX group had significantly higher alveolar bone loss and 8-OHdG compared to the control. The PTX group had significantly lower gingival SOD, GPx and CAT activity than the control groups. The PTX group had significantly higher relative gene expression of SCN9A (p = 0.0002) and TRPA1 (p = 0.0002) than the control in gingival tissues. Increased nociceptive susceptibility may affect the increase in oxidative stress and periodontal destruction. Chronic pain conditions may increase TRPA1 and SCN9A gene expression in the periodontium. The data of the current study may help develop novel approaches both to maintain periodontal health and alleviate pain in patients suffering from orofacial pain.

Remodeling periodontal osteoimmune microenvironment through MAPK/NFκB phosphorylation pathway of macrophage via intelligent ROS scavenging.

Periodontitis is an inflammatory disorder which leads to the defect of tooth-supporting tissue, especially in alveolar bone. During this process, the polarization behavior of macrophages affects immune inflammation and bone regeneration in which reactive oxygen species (ROS) play an essential role. ROS level should be regulated to the physiological level to protect stem cells from the inflammatory immune microenvironment. Our previous study constructed a ROS-responsive nanoplatform (Pssl-NAC), which possessed ROS-responsive antioxidative effect and could be potentially applied in periodontitis. However, the connection among bone regeneration, inflammation and oxidative stress remained in osteoimmune regulation is not clear. To further investigate the mechanism of the way how Pssl-NAC works in the treatment of periodontitis would be meaningful. Here, we investigated the effect of PssL-NAC in the regulation of the osteoimmune microenvironment through macrophage polarization. Results show PssL-NAC regulated the macrophage polarization direction in an inflammatory environment by maintaining an appropriate level of intracellular ROS, in which the MAPK/NFκB phosphorylation pathway is particularly important. In the macrophage-human periodontal ligament stem cells (hPDLSCs) co-culture system, PssL-NAC treatment significantly enhanced the osteogenic differentiation of hPDLSCs. In vivo experiment further confirmed the M2-like macrophages increased in the periodontal tissue of rats, and the expression of iNOS and p65 decreased after PssL-NAC treatment. In conclusion, PssL-NAC regulates the osteoimmune microenvironment and protects stem cells from oxidative stress injury for bone regeneration, which provides a strategy for the treatment of periodontitis.

Effect of recombinant human fibroblast growth factor 21 on the mineralization of cementoblasts and its related mechanism.

To investigate the effect of recombinant human fibroblast growth factor 21 (rhFGF21) on the proliferation and mineralization of cementoblasts and its mechanism. Hematoxylin eosin, immunohistochemical staining, and immunofluorescence were used to detect the expression and distribution of fibroblast growth factor 21 (FGF21) in rat periodontal tissues and cementoblasts (OCCM-30), separately. Cell Counting Kit-8 was used to detect the proliferation of OCCM-30 under treatment with rhFGF21. Alkaline phosphatase staining and Alizarin Red staining were used to detect the mineralization state of OCCM-30 after 3 and 7 days of mineralization induction. The transcription and protein expression of the osteogenic-related genes Runx2 and Osterix were detected by real-time quantitative polymerase chain reaction (PCR) and Western blot analysis. The expression levels of genes of transforming growth factor β (TGFβ)/bone morphogenetic protein (BMP) signaling pathway in OCCM-30 were detected through PCR array analysis. FGF21 was expressed in rat periodontal tissues and OCCM-30. Although rhFGF21 had no significant effect on the proliferation of OCCM-30, treatment with 50 ng/mL rhFGF21 could promote the mineralization of OCCM-30 cells after 7 days of mineralization induction. The transcriptional levels of Runx2 and Osterix increased significantly at 3 days of mineralization induction and decreased at 5 days of mineralization induction. Western blot analysis showed that the protein expression levels of Runx2 and Osterix increased during mineralization induction. rhFGF21 up-regulated Bmpr1b protein expression in cells. rhFGF21 can promote the mineralization ability of OCCM-30. This effect is related to the activation of the TGFβ/BMP signaling pathway.

Differential expression of lncRNA in periodontal tissue of rats in model of orthodontic tooth movement.

Differential expression of lncRNA in periodontal tissue of rats in model of orthodontic tooth movement.

Strontium ranelate inhibits alveolar bone resorption in diabetic rats with periodontitis by regulating JAK2/STAT3 signaling pathway

Purpose: To investigate the inhibitory effect of strontium ranelate on alveolar bone resorption in diabetic rats with periodontitis, and the mechanism involved.Methods: Forty-five Sprague-Dawley (SD) rats were allocated to 3 groups, viz, diabetic control, diabetic periodontitis, and diabetic periodontitis + strontium ranelate groups. Diabetes was induced via i.v. administration of streptozotocin (STZ) (45 mg/kg). Then, a rat model of periodontitis was established by ligating the neck of the upper left first molar of each rat with a 0.4-mm orthodontic ligation wire. Strontium ranelate or normal saline was administered by gavage. Four weeks later, various indicators were assessed.Results: There was a significantly higher expression level of Mir-21 in the periodontal tissue of diabetic periodontitis rats than in diabetic control rats. In contrast, this parameter was significantly lower in diabetic periodontitis rats than in periodontal tissues of rats in the diabetic periodontitis + strontium ranelate group, while the translations of JAK2 and STAT3 genes were significantly higher in periodontal tissues of diabetic periodontitis rats (p &lt; 0.05). In contrast, there were lower expression levels of JAK2 and STAT3 in diabetic periodontitis group than in diabetic periodontitis + strontium ranelate group (p &lt; 0.05).Conclusion: Strontium ranelate increases the expression level of miR-21 and activates JAK2/STAT3 signaling pathway, thereby inhibiting the resorption of alveolus bone in rats with diabetes/periodontitis.

The Examination of Remodeling Processes of Hard Periodontal Tissues in Rats with Disorders of Pancreatic Incretory Function

Topicality. Pancreatic hormones play an important role in the process of remodeling of hard periodontal tissues. Violations of carbohydrate metabolism that occur under conditions of isolated insulin resistance (IR) and in combination with iodine deficiency (ID) can be the cause of dysmetabolic disorders of mineralization/demineralization physiological system of tooth-maxillary complex.&#x0D; The aim. To study the changes of remodeling processes of hard periodontal tissues in rats with isolated IR and impaired glucose tolerance against the background of ID.&#x0D; Materials and methods. The examination was carried on 90 male rats, which were divided into three groups: control (intact animals), group of rats with IR under conditions of adequate iodine supply, and with IR against the background of ID. The system of carbohydrate metabolism was studied by the level of insulin in blood serum, glucose and glycosylated hemoglobin (HbA1c) of blood with the following calculation of HOMA-IR index. The processes of mineralization/demineralization were detected by the content of calcium, magnesium, zinc, manganese, copper in cementum of tooth root and alveolar process, and by the activity of acid and alkaline phosphatases in blood serum.&#x0D; Results. Keeping of animals on a high-fructose diet led to the development of carbohydrate metabolism disorders (increase blood glucose and HbA1c levels, blood serum insulin, HOMA-IR index) and changes of remodeling processes in hard periodontal tissues (decrease the level of calcium, magnesium and manganese against the background of increase the zinc content in cementum of tooth root; decrease the content of macroelements in alveolar process; activation of acid phosphatase against the background of inhibition of alkaline phosphatase activity). The development of combined endocrinopathy was accompanied by more pronounced changes of studied parameters.&#x0D; Conclusions. The violation of glucose tolerance against the background of ID slows down the mineralization processes of hard periodontal tissues mainly due to the intensification of osteoresorptive processes.&#x0D; Keywords: acid and alkaline phosphatases; calcium homeostasis; bioelement panel of tooth-maxillary system; insulin resistance; iodine deficiency.

Probiotic consumption can modify the resilience of periodontal tissues in rats under experimental periodontitis.

This study evaluated the effects of systemic administration of Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019) on experimental periodontitis (EP) in rats. Thirty-two rats were allocated to groups C (control), C-HN019 (probiotic), EP (EP only), and EP-HN019 (EP+probiotic). From day 0, the animals of C-HN019 and EP-HN019 groups received B. lactis HN019 (1×109 CFU/ml) daily. On the 14th day, the animals of EP and EP-HN019 groups received silk ligature around mandibular molars. Animals were euthanized on the 28th day. Samples of oral biofilm, gingival tissues, blood serum, and mandible were obtained for microtomographic, histomorphometric, microbiological, and immunological analyses. Data were statistically analyzed (p<0.05). Group EP-HN019 presented significantly less alveolar bone loss when compared with Group EP in histomorphometric and microtomographic analyses. In gingival tissue and serum, Group EP-HN019 presented lower proinflammatory/anti-inflammatory cytokines ratios than Group EP. Group EP-HN019 showed higher expression of beta-defensins and less TRAP-positive cells than Group EP. Group EP presented higher gene expression of Ifng and lower gene expression of Foxp3 when compared with Group EP-HN019 in gingival tissue. In oral biofilm, EP-HN019 group presented a lower percentage of species similar to Fusobacterium periodonticum and a higher percentage of species similar to Actinomyces gereneseriae, Actinomyces israelli, and Streptococcus gordonii when compared with Group EP. There was a significant increase of B. lactis HN019 after administration of probiotic therapy in oral biofilm of Group EP-HN019. The consumption of B. lactis HN019 promotes a protective effect against alveolar bone loss by modifying local and systemic microbiological and immunoinflammatory parameters.

Effects of Bdellovibrio bacteriovorus HD100 on experimental periodontitis in rats.

The aim of this study was to evaluate the effects of Bdellovibrio bacteriovorus HD100 on experimental periodontitis (EP) in rats. Thirty-two rats were divided into four groups: control, C-HD100 (B. bacteriovorus), EP, and EP-HD100. On day 0, EP was induced by the placement of cotton ligatures around the mandibular first molars (MFMs) in the EP and EP-HD100 groups. In the C-HD100 and EP-HD100 groups, suspensions containing 1×109 PUF/ml of B. bacteriovorus HD100 were topically administered to the subgingival region of MFMs on days 0, 3, and 7. Animals were euthanized on day 14. Morphometrics analyses were performed in hemimandibles. The levels of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, IL-10, IL-1β, transforming growth factor beta (TGF-β), macrophage colony-stimulating factor (M-CSF) and regulated on activation and normal T cell expressed and secreted (RANTES) were determined by enzymatic immunoassays in gingival tissues. Beta defensin (BD)-1, BD-2, and BD-3, Toll-like receptors (TLR)-2 and TLR-4, and a cluster of differentiation (CD)-4, CD-8 and CD-57 were analyzed by immunohistochemistry in hemimandibles. Data were statistically analyzed. The EP group showed greater alveolar bone loss than EP-HD100 (p<.05). The EP-HD100 group showed higher levels of MCP-1, RANTES, IL-10, and TGF-β, lower levels of TNF-α than the EP group (p<.05). No differences were observed in IL-1β, IL-6, and M-CSF levels between EP and EP-HD100 groups. The C-HD100 group had higher IL-6, TNF-α, RANTES, and MCP-1 levels than the control group (p<.05). Regarding BD, the EP-HD100 group showed a larger immunolabeling pattern for BD-1, BD-2, and BD-3 than the EP group (p<.05). No significant differences in the immunolabeling pattern were observed for TLR-2, TLR-4, CD-4, CD-8, and CD-57 between EP and EP-HD100 groups. The topical use of B. bacteriovorus HD100 reduces alveolar bone loss, increases expression of BD, and modulates the cytokines levels on periodontal tissues in rats with EP.

Mechanical force regulates root resorption in rats through RANKL and OPG

BackgroundExternal root resorption is one of common complications of orthodontic treatment, while internal root resorption is rarely observed, and the difference between pulp and periodontal tissues during orthodontic treatment is still unknown. The purpose of this study was to evaluate the effects of orthodontic forces on histological and cellular changes of the dental pulp and periodontal tissues.MethodsOrthodontic tooth movement model was established in Forty-eight adult male Wistar rats. The distance of orthodontic tooth movement was quantitatively analyzed. The histological changes of pulp and periodontal tissues were performed by hematoxylin–eosin staining, tartrate-resistant acid phosphate staining was used to analyze the changes of osteoclast number, immunohistochemistry analysis and reverse transcription polymerase chain reaction were used to examine the receptor of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) expression. The width of tertiary dentine was quantitatively analyzed. Tartrate-resistant acid phosphate staining and the erosion area of osteo assay surface plate was used to evaluate osteoclast activity.ResultsThe orthodontic tooth movement distance increased in a force dependent manner, and reached the peak value when orthodontic force is 60 g. Heavy orthodontic force increased the RANKL expression of periodontal ligament srem cells (PDLSCs) which further activated osteoclasts and resulted in external root resorption, while the RANKL expression of dental pulp stem cells (DPSCs) was relatively low to activate osteoclasts and result in internal root resorption, and the dental pulp tend to form tertiary dentine under orthodontic force stimulation.ConclusionsHeavy orthodontic forces activated osteoclasts and triggered external root resorption by upregulating RANKL expression in rat periodontal tissues, while there was no significant change of RANKL expression in dental pulp tissue under heavy orthodontic forces, which prevented osteoclast activation and internal root resorption.

Protective Effect of Iron Oxide Nanoparticles on Periodontal Injury in Rats by Inhibiting Collagenase-1 and Alkaline Phosphatase Expression

This study intends to assess whether iron oxide nanoparticles affect periodontal injury and collagenase-1 (COL-1), and alkaline phosphatase (ALP) in rats. In this study, the ALP activity and Col-1 concentration in rats with periodontal injury were determined.We detected the periodontal histopathological changes and expression of periodontal pocket depth (PD) and attachment loss (AL) by Hematoxylin and eosin (HE) staining.We also detected Col-1 and ALP proteins in periodontal tissues by Western blot. Real-time reverse transcription-polymerase chain reaction (RT-PCR) detected Col-1 and ALP mRNA level in periodontal tissues of rats in each group, while ALP activity and Col-1 concentration in gingival crevicular fluid in model group increased compared to sham group (P < 0.05). After intervention by iron oxide nanoparticles, ALP activity and Col-1 concentration in the gingival crevicular fluid of model rats decreased greatly (P < 0.05). The gingival atrophy was more serious in model group, and many inflammatory cells infiltrated into the tissue and destroyed the alveolar tissue. Meanwhile, the periodontal tissue from rats in intervention group was greatly improved, and the degree of alveolar bone destruction was also significantly reduced, while the PD and AL periodontal indexes were significantly inhibited (P < 0.05). The protein and relative expression showed that the protein and mRNA expressions of ALP and Col-1 in periodontal tissue from model group were lower than those in sham group (P < 0.05). After intervention by iron oxide nanoparticles, the protein and mRNA expressions of ALP and Col-1 in the periodontal tissues in intervention group increased (P < 0.05). Iron oxide nanoparticles can thus inhibit the expression of ALP and COL-1 in periodontal injury rats, and improve the periodontal injury tissue.

Effect of Bacterial Infection on Ghrelin Receptor Regulation in Periodontal Cells and Tissues.

The effect of bacterial infection on the expression of growth hormone secretagogue receptor (GHS-R) was investigated in periodontal cells and tissues, and the actions of ghrelin were evaluated. GHS-R was assessed in periodontal tissues of rats with and without periodontitis. Human gingival fibroblasts (HGFs) were exposed to Fusobacterium nucleatum in the presence and absence of ghrelin. GHS-R expression was determined by real-time PCR and immunocytochemistry. Furthermore, wound healing, cell viability, proliferation, and migration were evaluated. GHS-R expression was significantly higher at periodontitis sites as compared to healthy sites in rat tissues. F. nucleatum significantly increased the GHS-R expression and protein level in HGFs. Moreover, ghrelin significantly abrogated the stimulatory effects of F. nucleatum on CCL2 and IL-6 expressions in HGFs and did not affect cell viability and proliferation significantly. Ghrelin stimulated while F. nucleatum decreased wound closure, probably due to reduced cell migration. Our results show original evidence that bacterial infection upregulates GHS-R in rat periodontal tissues and HGFs. Moreover, our study shows that ghrelin inhibited the proinflammatory actions of F. nucleatum on HGFs without interfering with cell viability and proliferation, suggesting that ghrelin and its receptor may act as a protective molecule during bacterial infection on periodontal cells.

The anti-nociceptive effect of BPC-157 on the incisional pain model in rats.

BackgroundThe pentadecapeptide BPC-157 has been shown to have anti-inflammatory and wound healing effects on multiple target tissues and organs. Peptides have potent anti-inflammatory effects on periodontal tissues in rats with periodontitis. Few studies have investigated the effect of BPC-157 on pain after dental procedures or oral surgeries. The purpose of the present study was to investigate the antinociceptive effects of BPC-157 on postoperative incisional pain in rats.MethodsSprague–Dawley rats were randomly divided into five groups: control (saline with the same volume), BPC10 (10 µg/kg of BPC-157), BPC20 (20 µg/kg of BPC-157), BPC40 (40 µg/kg of BPC-157), and morphine (5 mg/kg of morphine). A 1-cm longitudinal incision was made through the skin, fascia, and muscle of the plantar aspect of the hind paw in isoflurane-anesthetised rats. Withdrawal responses were measured using von Frey filaments at 0, 2, 6 h and 4, 7 d after incision. The formalin test was also performed to differentiate its anti-nociceptive effect from an inflammatory reaction or central sensitization. Pain behavior was quantified periodically in phases 1 and 2 by counting the number of flinches in the ipsilateral paw after injection with 30 µL of 5% formalin.ResultsThe threshold of mechanical allodynia was significantly increased in the BPC10, BPC20, BPC40 and morphine groups compared with that in the control group at 2 h. These increasing thresholds then returned to the levels of the control group. The BPC-157 group showed a much higher threshold at 4 days after incision than the control group. The thresholds of the BPC groups, except the morphine group, were normalized 7 days after incision.The flinching numbers of the BPC10, BPC20, BPC40 and morphine groups were significantly decreased in phase 1, but there was no decrease in the BPC-157 groups except the morphine group in phase 2.ConclusionsBPC-157 was effective only for a short period after incision. It was also effective during phase 1 but not during phase 2, as determined by the formalin test. BPC-157 might have a short antinociceptive effect, even though it has anti-inflammatory and wound healing effects.

Levels of Hsp60 in periodontal tissue of rats: influence of injections of hyaluronic acid

Heat shock protein 60 (Hsp60) is considered as one of the possible autoantigens involved in the pathogenesis of a number of chronic diseases including periodontal diseases. The application of hyaluronic acid or hyaluronan (HA) in the treatment of periodontitis has been evaluated in several clinical trials, however, the effect of hyaluronic acid on heat shock protein 60 level in periodontal soft tissues has not been studied. The aim of this work was to evaluate the effect of HA injections on levels of Hsp60 in periodontal tissue of the rats. Samples of periodontal tissue of mandibular incisors of adult male Wistar rats at 10-12 months of age were investigated. Rats were distributed into the control group and the periodontitis group. Visual manifestations of hyperemia of the gums around the incisors were the criterion for selecting animals into the periodontitis group. There were two subgroups in the control group: intact rats (I); intact rats after HA “hyaDENT BG” 1.0 MDa (BioScience GmbH, Germany) treatment (I+“G-1.0”). There were four subgroups in the periodontitis group: rats with periodontitis (P); rats with periodontitis after HA “hyaDENT BG” 1.0 MDa (BioScience GmbH, Germany) treatment (P+“G-1.0”); rats with periodontitis after HA “SERTOBEC” 2.4 MDa (S.C. Rompharm Company S.R.L., Romania) treatment (P+“S-2.4”); rats with periodontitis after HA “SERTOBEC Tendon” 2.4 МDа (S.C. Rompharm Company S.R.L., Romania) treatment (P+“ST-2.4”). There were three animals in each subgroup. Rats were injected 0.05 ml HA in the area of alveolar processus of central incisors once a week, three times. Levels of Hsp60 in total lysates of periodontal tissue were tested by Western blotting method before and after the treatment with HA (one month after the last injection). There was no significant difference between levels of Hsp60 in total lysates of periodontal tissue of intact rats and rats with periodontitis before treatment (p&gt;0.05). Rats with periodontitis showed decreased inflammation in the periodontal tissue after treatment with HA with different molecular weight. Intact rats and rats with periodontitis which were treated with HA “hyaDENT BG” 1.0 MDa showed reduced levels of Hsp60 in total lysates of periodontal tissue comparatively with levels of Hsp60 before treatment (by 15.4 and 10.7 times respectively, p&lt;0.001). Rats with periodontitis which were treated with HA “SERTOBEC” 2.4 MDa or HA “SERTOBEC Tendon” 2.4 MDa also showed reduced levels of Hsp60 in total lysates of periodontal tissue com­paratively with levels of Hsp60 before treatment (by 21.3 and 16.4 times respectively, p&lt;0.001). Rats with pe­riodontitis showed the decrease in inflammation in periodontal tissue after treatment with HA with different molecular weight. Injections of HA has contributed to reduce levels of Hsp60 in periodontal tissue of intact rats and rats with periodontitis.

Influence of new dental elixir on rats periodontal tissues with modeling of metabolic syndrome

Aim: to study the changes in the periodontal tissues of rats with simulation of metabolic syndrome of alimentary genesis and to determine a possibility of their correction with the new dental elixir.Materials and methods: Biochemical changes in the blood serum, liver and gingival tissue were examined during simulation of the metabolic syndrome of alimentary genesis in experiment on 28 white male rats of reproductive age with an average body weight (280±14)g.Results. It was found that keeping animals for ten weeks on a diet high in saturated fats and carbohydrates led to increase in body weight and in level of biochemical markers: insulin resistance, hyperglycemia, inflammation, both at the level of the body and locally in the periodontal tissues. Local application of the new dental elixir in the form of applications to rats gums against the background of metabolic syndrome reduced the level of triglycerides, had an anti-inflammatory and antioxidant effect, reducing contamination by pathogenic microflora (urease activity), lipid peroxidation activity (malonic dialdehyde content), activating locally in the periodontal tissues the antioxidant defense enzyme and nonspecific immunity — lysozyme.Conclusions. The use of the new oral hygiene product in experimental metabolic syndrome improved metabolism, reduced inflammation, presenting periodontal protective properties, which allows to offer it for clinical testing in patients with periodontitis against a background of metabolic syndrome.