Improved microvascular reactivity after aged garlic extract intake is not mediated by hydrogen sulfide in older adults at risk for cardiovascular disease: a randomized clinical trial.

PURPOSE: This study aimed to investigate the effects of AGE on microvascular reactivity, systolic blood pressure (SBP), and diastolic blood pressure (DBP) in older individuals at high risk for cardiovascular disease (CVD). Urinary thiosulfate was also investigated as an indirect marker of endogenous hydrogen sulfide (H2S) synthesis. The study was conducted in a randomized, double-blind, crossover, and placebo-controlled way. METHODS: Twenty-eight participants (14 male), 67 ± 6 years old with CVD risk factors, ingested 2.4 g of AGE or placebo (PLA). Near-infrared spectroscopy evaluated tissue oxygen saturation (StO2) during a vascular occlusion test (30 s baseline, 5 min occlusion, and 2 min reperfusion). The upslope of StO2 signal after cuff release was calculated to measure microvascular reactivity. Urinary thiosulfate levels were measured using a high-performance liquid chromatography system. RESULTS: The upslope of StO2 was significantly faster after AGE (1.01 ± 0.37% s-1) intake compared to PLA (0.83 ± 0.35% s-1; P < 0.001; d = 0.50). Relative changes in Δ% SBP from pre- to post-AGE intake (- 5.17 ± 5.77%) was significantly different compared to Δ% PLA (0.32 ± 5.99%; P = 0.001; d = 0.93). No significant changes in urinary thiosulfate concentrations were observed between interventions. Moreover, no significant gender effect in any parameter assessed was found. CONCLUSION: This study demonstrated that a single dose of AGE improved microvascular reactivity in older adults at risk of CVD despite such an effect was not linked with urinary thiosulfate levels. This trial was registered at clinicaltrials.gov as NCT04008693 (May 19, 2020).

Bisphosphonate-related osteonecrosis induced change in alveolar bone architecture in rats with participation of Wnt signaling.

OBJECTIVE: This work aimed to study the role of inflammation in medication-related osteonecrosis of the jaw (MRONJ) in rats with focus on Wnt signaling. METHODS: A total of 36 female Wistar rats (12 weeks ± 200 g) were divided into 2 groups (n = 6) in 3 experiments: saline (SAL) and zoledronic acid (ZOL). For MRONJ induction, rats received 0.1 mg/kg of ZOL (ip) 3×/week for 9 weeks. Animals from the SAL group received 0.1 mg/kg of 0.9% SAL, ip 3×/week for 9 weeks. On the 8th week, 3 left upper molars were extracted, and on the 11th week, they were euthanized. Maxillae were evaluated by macroscopic and histopathological analyses; scanning electron microscopy (SEM); immunohistochemistry for DKK-1, Wnt 10b, and caspase-3; and Raman spectrometry. Gingiva was also collected for TNF-α e IL-1ß quantification. RESULTS: Bone necrosis was confirmed by healing impairment, reduced number of viable osteocytes, increased caspase-3 immunoexpression, and increased number of empty lacunae (p < 0.05). ZOL enhanced inflammation and increased gingival levels of IL-1ß and TNF-α (p < 0.05). Irregular indentations were seen on bone after ZOL administration. Bone necrosis was marked by reduced amount of total and type I collagen. ZOL reduced the mineral/matrix ratio and increased carbonate/phosphate ratio. It was observed a significant reduction on Wnt10b and beta-catenin immunolabeling in the bone tissue of ZOL group. CONCLUSION: In summary, MRONJ model caused bone necrosis due to intense inflammation. Wnt signaling seems to play an important role in this process. CLINICAL RELEVANCE: New therapeutic strategies focusing on Wnt pathway can provide an interesting approach for future treatments.

The Receptor AT1 Appears to Be Important for the Maintenance of Bone Mass and AT2 Receptor Function in Periodontal Bone Loss Appears to Be Regulated by AT1 Receptor.

A large number of experimental studies has demonstrated that angiotensin II (Ang II) is involved in key events of the inflammatory process. This study aimed to evaluate the role of Ang II type 1 (AT1) and Ang II type 2 (AT2) receptors on periodontitis. Methods: Experimental periodontitis was induced by placing a 5.0 nylon thread ligature around the second upper left molar of AT1 mice, no-ligature or ligature (AT1-NL and AT1-L), AT2 (AT2-NL or AT2-L) and wild type (WT-NL or L). Alveolar bone loss was scanned using Micro-CT. Cytokines, peptides and enzymes were analyzed from gingival tissues by Elisa and RT-PCR. Results: The blockade of AT1 receptor resulted in bone loss, even in healthy animals. Ang II receptor blockades did not prevent linear bone loss. Ang II and Ang 1-7 levels were significantly increased in the AT2-L (p < 0.01) group compared to AT2-NL and AT1-L. The genic expression of the Mas receptor was significantly increased in WT-L and AT2-L compared to (WT-NL and AT2-NL, respectively) and in AT1-L. Conclusions: Our data suggest that the receptor AT1 appears to be important for the maintenance of bone mass. AT2 receptor molecular function in periodontitis appears to be regulated by AT1.

AT1 and AT2 Receptor Knockout Changed Osteonectin and Bone Density in Mice in Periodontal Inflammation Experimental Model.

BACKGROUND: The aim of this study was to evaluate the role of AT1 and AT2 receptors in a periodontal inflammation experimental model. METHODS: Periodontal inflammation was induced by LPS/Porphyromonas gingivalis. Maxillae, femur, and vertebra were scanned using Micro-CT. Maxillae were analyzed histopathologically, immunohistochemically, and by RT-PCR. RESULTS: The vertebra showed decreased BMD in AT1 H compared with WT H (p < 0.05). The femur showed increased Tb.Sp for AT1 H and AT2 H, p < 0.01 and p < 0.05, respectively. The Tb.N was decreased in the vertebra (WT H-AT1 H: p < 0.05; WT H-AT2 H: p < 0.05) and in the femur (WT H-AT1 H: p < 0.01; WT H-AT2 H: p < 0.05). AT1 PD increased linear bone loss (p < 0.05) and decreased osteoblast cells (p < 0.05). RANKL immunostaining was intense for AT1 PD and WT PD (p < 0.001). OPG was intense in the WT H, WT PD, and AT2 PD when compared to AT1 PD (p < 0.001). AT1 PD showed weak immunostaining for osteocalcin compared with WT H, WT PD, and AT2 PD (p < 0.001). AT1 H showed significantly stronger immunostaining for osteonectin in fibroblasts compared to AT2 H (p < 0.01). CONCLUSION: AT1 receptor knockout changed bone density, the quality and number of bone trabeculae, decreased the number of osteoblast cells, and increased osteonectin in fibroblasts.

In vitro-in vivo availability of metformin hydrochloride-PLGA nanoparticles in diabetic rats in a periodontal disease experimental model.

CONTEXT: Metformin is an important oral anti-hyperglycemic used in diabetes. Polylactic-co-glycolic acid (PLGA) has been widely used due to its reliability in controlling the release of drugs. OBJECTIVE: This study evaluates the in vitro-in vivo availability of metformin hydrochloride-loaded polylactic-co-glycolic acid. MATERIAL AND METHODS: In vitro metformin release (Met-free or PLGA + Met-12.5 mg/mL per 360 min) was evaluated using static Franz vertical diffusion cells. The in vivo study was performed with two control groups (validation bioanalytical method) and two experimental groups of diabetic male Wistar rats treated with PLGA + Met 10 mg/kg or Met 100 mg/kg by oral gavage. Diabetes was induced by streptozotocin (40 mg/kg) through the penile vein. Blood samples were collected 0.5, 1, 4, 7, 10, 12, 18, 24, 36, 48 and 72 h and analysed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). RESULTS: PLGA + Met 10 mg/kg was released in the in vitro assay suggesting a parabolic diffusion kinetic model (K -0.0619-0.5h) with a 100% release profile in 10 h by controlled diffusion. The in vivo assay showed the apparent volume of distribution Vz/F (PLGA + Met 10 mg/kg, 40971.8 mL/kg vs. Met 100 mg/kg, 2174.58 mL/kg) and mean residence time MRTinf (PLGA + Met 10 mg/kg, 37.66 h vs. Met 100 mg/kg, 3.34 h). DISCUSSION AND CONCLUSIONS: The formulation modifies pharmacokinetics parameters such as apparent distribution volume and mean residence time. The PLGA + Met 10 mg/kg had a slower elimination rate compared to Met 100 mg/kg in diabetic rats in a periodontal disease experimental model.

Anti-inflammatory latex proteins of the medicinal plant Calotropis procera: a promising alternative for oral mucositis treatment.

OBJECTIVE AND DESIGN: Oral mucositis (OM) is an intense inflammatory reaction progressing to tissue damage and ulceration. The medicinal uses of Calotropis procera are supported by anti-inflammatory capacity. PII-IAA, a highly homogenous cocktail of laticifer proteins (LP) prepared from the latex of C. procera, with recognized pharmacological properties was tested to treat OM. MATERIALS AND SUBJECTS: Male Golden Sirius hamsters were used in all treatments. TREATMENT: The latex protein samples were injected i.p. (5 mg/Kg) 24 h before mucositis induction (mechanical trauma) and 24 h later. METHODS: Histology, cytokine measurements [ELISA], and macroscopic evaluation [scores] were performed. RESULTS: PII-IAA eliminated OM, accompanied by total disappearance of myeloperoxidase activity and release of IL-1b, as well as reduced TNF-a. Oxidative stress was relieved by PII-IAA treatment, as revealed by MDA and GSH measurements. PII-IAA also reduced the expression of adhesion molecules (ICAM-1) and Iba-1, two important markers of inflammation, indicating modulatory effects. Histological analyses of the cheek epithelium revealed greater deposition of type I collagen fibers in animals given PII-IAA compared with the control group. This performance was only reached when LPPII was treated with iodoacetamide (IAA), an irreversible inhibitor of proteolytic activity of cysteine proteases. The endogenous proteolytic activity of LPPII induced adverse effects in animals. Candidate proteins involved in the phytomodulatory activity are proposed. CONCLUSIONS: Therapy was successful in treating OM with the laticifer protein fraction, containing peptidases and osmotin, from Calotropis procera. The effective candidate from the latex proteins for therapeutic use is PII-IAA.

Anti-inflammatory and antiresorptive effects of Calendula officinalis on inflammatory bone loss in rats.

OBJECTIVE: The aim of this work was to evaluate the anti-inflammatory and antiresorptive effects of Calendula officinalis (CLO) on alveolar bone loss (ABL) in rats. MATERIAL AND METHODS: Male Wistar rats were subjected to ABL by ligature with nylon thread around the second upper left molar. The contralateral hemimaxillae were used as control. Rats received saline solution (SAL) or CLO (10, 30, or 90 mg/kg) 30 min before ligature and daily until the 11th day. The maxillae were removed and prepared for macroscopic, radiographic, micro-tomographic, histopathologic, histometric analysis, and immunohistochemical localization of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG). The gingival tissues were used to quantify the myeloperoxidase (MPO) activity, tumor necrosis factor-alpha (TNF-α), and interleukin-1ß (IL-1ß) concentrations by ELISA. Blood samples were collected for leukogram and to evaluate the bone-specific alkaline phosphatase (BALP) activity and serum levels of aspartate and alanine transaminases (AST/ALT). RESULTS: The bone loss induced by 11 days of ligature induced bone loss, reduced levels of BALP, leukocyte infiltration, increased MPO activity, gingival concentrations of TNF-α and IL-1ß, and RANKL while reduced OPG immunoexpressions in the periodontal tissue and leukocytosis. Of the CLO, 90 mg/kg reduced bone loss, neutrophilia, the levels of pro-inflammatory mediators, and RANKL expression, while it increased OPG immunopositive cells and BALP serum levels, when compared to SAL. CLO did not affect either kidney or liver function, indicated by serum AST/ALT levels. CONCLUSION: The present data suggests that CLO reduced inflammatory bone resorption in experimental periodontitis, which may be mediated by its anti-inflammatory properties and its effects on bone metabolism. CLINICAL RELEVANCE: CLO can be a potential therapeutical adjuvant in the treatment of periodontitis.

Polysacharide of Agaricus blazei gel mitigates bone necrosis in model of the jaws related to bisphosphonate via Wnt signaling.

To investigate de effect of PAb gel on the bone tissue of rats submitted to Bisphosphonate-related osteonecrosis of the jaws (BRONJ). Initially, 54 animals were submitted to BRONJ model by Zoledronic Acid (ZA) (0.1 mg/kg 3x/wk for 9 wk, ip), followed by the 1st upper left molar extraction at the 8th wk. After tooth removal, the animals were divided into 3 groups, ZA that received placebo gel or PAb gel that received 1% PAb gel, inside the dental alveolus. The control Group (CONTROL) received 0.1 mg/kg of 0.9% saline and then placebo gel. Three weeks after tooth extraction, the animals were euthanized, and maxillae were colleted for macroscopic, radiographic, histological and Raman spectomery assays. Additionally, GSK3b, beta-catenin, and Runx2 mRNA expressions were determined. Blood samples were collected for the analysis of Bone-specific alkaline phosphatase (BALP) levels. PAb gel improved mucosal healing, increased the number of viable osteocytes, while it reduced the number of empty lacunae, as well as the amount of bone sequestration. Furthermore, PAb gel positively influenced the number and functionality of osteoblasts by stimulating Wnt signaling, thereby inducing bone remodeling. Additionally, PAb gel contributed to improved bone quality, as evidenced by an increase in bone mineral content, a decrease in bone solubility, and an enhancement in the quality of collagen, particularly type I collagen. PAb gel mitigated bone necrosis by stimulating of bone remodeling through Wnt signaling and concurrently improved bone quality. PAb gel emerges as a promising pharmacological tool for aiding in BRONJ therapy or potentially preventing the development of BRONJ.

Agaricus blazei Murill polysaccharides/alginate/poly(vinyl alcohol) blend as dressings for wound healing.

Macromolecules with antioxidant properties such as polysaccharides from Agaricus blazei Murill mushroom (PAbs) are an excellent option for manufacturing wound dressings. Based on this, this study aimed to analyze preparation, physicochemical characterization, and assessment of the potential wound-healing activity of films based on sodium alginate and polyvinyl alcohol loaded with PAbs. PAbs did not significantly alter the cell viability of human neutrophils in a concentration range of 1-100 µg mL-1. The Infrared Spectroscopy (FTIR) indicates that the components present in the films (PAbs/Sodium Alginate (SA)/Polyvinyl Alcohol (PVA)) present an increase in hydrogen bonds due to the increase of hydroxyls present in the components. Thermogravimetry (TGA), Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD) characterizations indicate a good miscibility between the components where PAbs increasing the amorphous characteristics of the films and that the addition of SA increased the mobility of the chains PVA polymers. The addition of PAbs to films significantly improves properties such as mechanical, thickness, and water vapor permeation. The morphological study evidenced good miscibility between the polymers. The wound healing evaluation indicated that F100 film presented better results from the fourth day onward compared to the other groups. It favored the formation of a thicker dermis (476.8 ± 18.99 µm), with greater collagen deposition and a significant reduction in malondialdehyde and nitrite/nitrate, markers of oxidative stress. These results indicate that PAbs is a candidate for wound dressing.

Successful Pre-Clinical Management of Irinotecan-Debilitated Animals: A Protein- Based Accessory Phytomedicine.

BACKGROUND: Calotropis procera is a laticiferous plant (Apocynaceae) found in tropical regions all over the world. The ultrastructural characteristics of laticifers, their restricted distribution among different taxonomic groups, and in some species in each clade, as peptidases from latex, make them very attractive for biological analysis. OBJECTIVE: The study aims to investigate the effects of LP-PII-IAA (laticifer protein (LP) sub-fraction II (PII) of C. procera presenting an iodoacetamide-inhibited cysteine proteinase activity) on irinotecan-induced intestinal mucositis, a serious adverse effect of this medicine for the treatment of cancer. METHODS: LP-PII-IAA is composed of closely related isoforms (90%) of peptidases derived from catalysis and an osmotin protein (5%). Animals receiving co-administration of LP-PII-IAA presented a significant decrease in mortality, absence of diarrhea, histological preservation, and normalization of intestinal functions. RESULTS: Clinical homeostasis was accompanied by a reduction in MPO activity and declined levels of IL-1ß, IL-6 and KC, while the IL-10 level increased in LP-PII-IAA-treated animals. COX-2 and NF-kB immunostaining was reduced and the levels of oxidative markers (GSH, MDA) were normalized in animals that received LP-PII-IAA. CONCLUSION: We suggest that peptidases from the latex of Calotropis procera were instrumental in the suppression of the adverse clinical and physiological effects of irinotecan.

The effect of high concentration of zoledronic acid on tooth induced movement and its repercussion on root, periodontal ligament and alveolar bone tissues in rats.

Zoledronic acid (ZA) is often prescribed for osteoporosis or resorptive metabolic bone disease. This study aims to evaluate the effect of ZA on orthodontic tooth movement (OTM) and root and bone resorption and its repercussion on root, periodontal ligament and alveolar bone tissues. The experimental group consisted of 72 Wistar rats divided in four subgroups: Naive, Saline and Zoledronic Acid groups at the concentration of 0.2 mg/kg [ZA (0.2)] or 1.0 mg/kg [ZA (1.0)]. The animals were subjected to i.v (dorsal penile vein) administrations of ZA or saline solution, on days 0, 7, 14 and 42. Under anesthesia, NiTi springs were installed in the first left maxillary molar with 50gf allowing the OTM, except for the negative control group (N) for mesial movement of the left first maxillary teeth. The animals were sacrificed and maxillae were removed for macroscopic and histopathological analyzes, scanning electron microscopy, computerized microtomography and confocal microscopy. Treatment with ZA decreased the OTM and the number of osteoclasts and loss of alveolar bone when compared to the naive and saline groups. Reduction of radicular resorption, increased necrotic areas and reduced vascularization in the periodontal ligament were observed in the ZA groups. ZA interferes with OTM and presents anti-resorptive effects on bone and dental tissues associated with a decreased vascularization, without osteonecrosis.

Alendronate sodium-polymeric nanoparticles display low toxicity in gastric mucosal of rats and Ofcol II cells.

The use of bisphosphonates constitutes the gold-standard therapy for the control and treatment of bone diseases. However, its long-term use may lead to gastric problems, which limits the treatment. Thus, this study aimed to formulate a nanostructured system with biodegradable polymers for the controlled release of alendronate sodium. The nanoparticles were characterized, and its gastric toxicity was investigated in rats. The synthesis process proved to be effective for encapsulating alendronate sodium, exhibiting nanoparticles with an average size of 51.02 nm and 98.5% of alendronate sodium incorporation. The release tests demonstrated a controlled release of the drug in 420 min, while the morphological analyzes showed spherical shapes and no apparent roughness. The biological tests demonstrated that the alendronate sodium nanoformulation reversed the gastric lesions, maintaining the normal levels of malondialdehyde and myeloperoxidase. Also, the encapsulated alendronate sodium showed no toxicity in murine osteoblastic cells, even at high concentrations.

5-Fluorouracil induces inflammation and oxidative stress in the major salivary glands affecting salivary flow and saliva composition.

This study aimed to elucidate the effect of 5-fluorouracil (5-FU) on the histological aspects of the major salivary glands, salivary flow and saliva composition using an established oral mucositis model in hamsters. Oral mucositis was induced by two intraperitoneal administrations of 5-FU in two consecutive days (60 and 40mg/kg), followed by cheek pouch mucosa scratch, on day 4. The Pilocarpine-stimulated salivary flow was measured 4 and 10days after the first 5-FU injection. Salivary glands were harvested for histopathological analysis, measurement of inflammatory cells, quantification of pro-inflammatory cytokines (TNF-α and IL-1ß), investigation of cell death and cell proliferation. Oxidative stress and oxidative defense system were also investigated in the salivary gland tissues using MDA (malondialdehyde), nitrite, non-protein sulfhydryl groups (NP-SH), SOD (superoxide dismutase) and CAT (catalase). In addition, the CAT and lysozyme activities and the IgA and SOD levels were evaluated in the saliva samples. 5-FU significantly reduced the pilocarpine-stimulated salivary flow rate on the 4th experimental day, associated with an increase in the SOD levels in saliva. Recovery of the salivary flow and SOD were observed on day 10, when an increase in the saliva lysozyme levels was detected. In addition, 5-FU promoted vacuolization in parotid (P) and periductal edema in submandibular (SM) gland, combined with an increase in the inflammatory cells influx, mostly observed on the 4th day in SM gland and on 4th and 10th days in P. Oxidative stress was found mostly on day 10 in SM, SL and P glands, associated with release of proinflammatory cytokines, observed in SM and SL glands, but not in P. 5-FU induces an inflammatory response in the major salivary glands, most observed ten days after its first injection, which may contribute to the major salivary glands hypofunction, leading to alterations in the salivary flow rate and composition.

Effects of metformin on inflammation, oxidative stress, and bone loss in a rat model of periodontitis.

AIM: To evaluate the effects of metformin (Met) on inflammation, oxidative stress, and bone loss in a rat model of ligature-induced periodontitis. MATERIALS & METHODS: Male albino Wistar rats were divided randomly into five groups of twenty-one rats each, and given the following treatments for 10 days: (1) no ligature + water, (2) ligature + water, (3) ligature + 50 mg/kg Met, (4) ligature + 100 mg/kg Met, and (5) ligature + 200 mg/kg Met. Water or Met was administered orally. Maxillae were fixed and scanned using Micro-computed Tomography (µCT) to quantitate linear and bone volume/tissue volume (BV/TV) volumetric bone loss. Histopathological characteristics were assessed through immunohistochemical staining for MMP-9, COX-2, the RANKL/RANK/OPG pathway, SOD-1, and GPx-1. Additionally, confocal microscopy was used to analyze osteocalcin fluorescence. UV-VIS analysis was used to examine the levels of malondialdehyde, glutathione, IL-1ß and TNF-α from gingival tissues. Quantitative RT-PCR reaction was used to gene expression of AMPK, NF-κB (p65), and Hmgb1 from gingival tissues. Significance among groups were analysed using a one-way ANOVA. A p-value of p<0.05 indicated a significant difference. RESULTS: Treatment with 50 mg/kg Met significantly reduced concentrations of malondialdehyde, IL-1ß, and TNF-α (p < 0.05). Additionally, weak staining was observed for COX-2, MMP-9, RANK, RANKL, SOD-1, and GPx-1 after 50 mg/kg Met. OPG and Osteocalcin showed strong staining in the same group. Radiographically, linear measurements showed a statistically significant reduction in bone loss after 50 mg/kg Met compared to the ligature and Met 200 mg/kg groups. The same pattern was observed volumetrically in BV/TV and decreased osteoclast number (p<0.05). RT-PCR showed increased AMPK expression and decreased expression of NF-κB (p65) and HMGB1 after 50 mg/kg Met. CONCLUSIONS: Metformin, at a concentration of 50 mg/kg, decreases the inflammatory response, oxidative stress and bone loss in ligature-induced periodontitis in rats.

Clinical efficacy of a 1% Matricaria chamomile L. mouthwash and 0.12% chlorhexidine for gingivitis control in patients undergoing orthodontic treatment with fixed appliances.

This pilot study evaluated the clinical efficacy of a mouthwash containing 1% Matricaria chamomilla L. (MTC) extract in reducing gingival inflammation and plaque formation in patients undergoing orthodontic treatment with fixed appliances. This randomized, double-blind, placebo-controlled study enrolled a total of 30 males and females (age, 10-40 years) with fixed orthodontic appliances and a minimum of 20 natural teeth. The participants were allocated to three groups (n = 10 each) and asked to rinse with 15 mL of a placebo, 0.12% chlorhexidine (CHX), or 1% MTC mouthwash, immediately after brushing for 1 min, in the morning and evening, for 15 days. Data (mean ± SD) on visible plaque index (VPI) and gingival bleeding index (GBI) were recorded on days 1 and 15. The placebo group exhibited increases in VPI and GBI (10.2% and 23.1%, respectively) from day 1 to day 15. As compared with placebo, VPI and GBI significantly decreased in the MTC group (-25.6% and -29.9%, respectively) and the CHX group (-39.9% and -32.0%, respectively). In summary, MTC reduced biofilm accumulation and gingival bleeding in patients with gingivitis, probably because of its antimicrobial and anti-inflammatory activities.(J Oral Sci 58, 569-574, 2016).

Topical HPMC/S-Nitrosoglutathione Solution Decreases Inflammation and Bone Resorption in Experimental Periodontal Disease in Rats.

S-nitrosoglutathione (GSNO) is a nitric oxide (NO) donor, which exerts antioxidant, anti-inflammatory, and microbicidal actions. Intragingival application of GSNO was already shown to decrease alveolar bone loss, inflammation and oxidative stress in an experimental periodontal disease (EPD) model. In the present study, we evaluated the potential therapeutic effect of topical applications of hydroxypropylmethylcellulose (HPMC)/GSNO solutions on EPD in Wistar rats. EPD was induced by placing a sterilized nylon (3.0) thread ligature around the cervix of the second left upper molar of the animals, which received topical applications of a HPMC solutions containing GSNO 2 or 10 mM or vehicle (HPMC solution), 1 h prior to the placement of the ligature and then twice daily until sacrifice on day 11. Treatment with HPMC/GSNO 10 mM solution significantly reduced alveolar bone loss, oxidative stress and TNF-α e IL-1ß levels in the surrounding gingival tissue, and led to a decreased transcription of RANK and TNF-α genes and elevated bone alkaline phosphatase, compared to the HPMC group. In conclusion, topical application of HPMC/GSNO solution is a potential treatment to reduce inflammation and bone loss in periodontal disease.

Guided bone regeneration produced by new mineralized and reticulated collagen membranes in critical-sized rat calvarial defects.

The aim of this study was to evaluate the bone regenerative effect of glutaraldehyde (GA) cross-linking on mineralized polyanionic collagen membranes in critical-sized defects on rat calvarias. Bone calvarial defects were induced in Wistar rats, which were then divided into five groups: a sham group; a control group, which received a commercial membrane; and GA, 25GA, and 75GA groups, which received one of three different polyanionic collagen membranes mineralized by 0, 25, or 75 hydroxyapatite cycles and then cross-linked by GA. Bone formation was evaluated based on digital radiography and computerized tomography. Histological analyses were performed 4 and 12 weeks after the surgical procedure to observe bone formation, membrane resorption, and fibrous tissue surrounding the membranes. Measurement of myeloperoxidase activity, tumor necrosis factor alpha, and interleukin 1beta production was performed 24 h after surgery. The percentage of new bone formation in the GA, 25GA, and 75GA groups was higher compared with the control and sham groups. In the GA and 25 GA groups, the membranes were still in place and were contained in a thick fibrous capsule after 12 weeks. No significant difference was found among the groups regarding myeloperoxidase activity and interleukin 1beta levels, although the GA, 25GA, and 75GA groups presented decreased levels of tumor necrosis factor alpha compared with the control group. These new GA cross-linked membranes accelerated bone healing of the calvarium defects and did not induce inflammation. In addition, unlike the control membrane, the experimental membranes were not absorbed during the analyzed period, so they may offer advantages in large bone defects where prolonged membrane barrier functions are desirable.

Infliximab attenuates inflammatory osteolysis in a model of periodontitis in Wistar rats.

Periodontitis is a chronic inflammatory disease related to tooth loss in adults. Infliximab is a chimeric monoclonal antibody against TNF-α and is prescribed for the treatment of systemic inflammatory diseases. This study aimed to investigate the role of infliximab on experimental periodontal disease (EPD). EPD was induced by passing a 3.0 nylon thread around the upper left second molar in Wistar rats. Animals were either treated with intravenous infliximab (1, 5, 7, and 10 mg/kg) or saline solution 30 min before the periodontitis induction and were followed until they were sacrificed on the 11th day. A subset of rats was euthanized on the third day for analysis of gingival myeloperoxidase (MPO) and the blood MPO granulocyte index. In addition, we analyzed the bone loss index (BLI), the periodontal histopathological score, and the periodontal collagen network using confocal microscopy. We also analyzed metalloproteinase-1/-8, RANK, RANK-L, and osteoprotegerin in maxillary tissue by immunohistochemistry Gingival MPO, IL-1ß, TNF-α were measured by ELISA. EPD caused leukocytosis, significant increases in BLI and gingival pro-inflammatory cytokines and cell infiltrates, with worse histopathological scores and periodontal collagen derangement. Infliximab (5 mg/kg) reduced granulocyte blood counts, gingival IL-1ß, TNF-α, and MPO levels, diminished MMP-1/-8, RANK, and RANK-L bone immunolabeling with better periodontal histopathological scores and collagen network in comparison with the challenged saline group. We concluded that infliximab had significant anti-inflammatory and bone-protective effects in Wistar rats challenged by periodontitis.

S-nitrosoglutathione decreases inflammation and bone resorption in experimental periodontitis in rats.

BACKGROUND: S-nitrosoglutathione (GSNO) is a nitric oxide donor that may exert antioxidant, anti-inflammatory, and microbicidal actions and is thus a potential drug for the topical treatment of periodontitis. In this study, the effect of intragingival injections of GSNO-containing polyvinylpyrrolidone (PVP) formulations is evaluated in a rat model of periodontitis. METHODS: Periodontal disease was induced by placing a sterilized nylon (000) thread ligature around the cervix of the second left upper molar of the animals, which received intragingival injections of PVP; saline; or PVP/GSNO solutions which corresponded to GSNO doses of 25, 100, and 500 nmol; 1 hour before periodontitis induction, and thereafter, daily for 11 days. RESULTS: PVP/GSNO formulations at doses of 25 and/or 100, but not 500 nmol caused significant inhibition of alveolar bone loss, increase of bone alkaline phosphatase, decrease of myeloperoxidase activity, as well as significant reduction of inflammatory and oxidative stress markers when compared to saline and PVP groups. These effects were also associated with a decrease of matrix metalloproteinases 1 and 8, inducible nitric oxide synthase, and nuclear factor-κB immunostaining in the periodontium. CONCLUSION: Local intragingival injections of GSNO reduces inflammation and bone loss in experimental periodontal disease.