Role of nitro-oxidative stress in the pathogenesis of experimental rat periodontitis

Investigation of Oxidative-Stress Impact on Human Osteoblasts During Orthodontic Tooth Movement Using an In Vitro Tension Model

In recent years, there has been a growing number of adult orthodontic patients with periodontal disease. The progression of periodontal disease is well-linked to oxidative stress (OS). Nevertheless, the impact of OS on orthodontic tooth movement (OTM) is not fully clarified. Therefore, we applied an OS in vitro-model utilizing H2O2 to study its effect on tension-induced mechanotransduction in human osteoblasts (hOBs). Experimental parameters were established based on cell viability and proliferation. Apoptosis detection was based on caspase-3/7 activity. Gene expression related to bone-remodeling (RUNX2, P2RX7, TNFRSF11B/OPG), inflammation (CXCL8/IL8, IL6, PTRGS2/COX2), autophagy (MAP1LC3A/LC3, BECN1), and apoptosis (CASP3, CASP8) was analyzed by RT-qPCR. IL6 and PGE2 secretion were determined by ELISA. Tension increased the expression of PTRGS2/COX2 in all groups, especially after stimulation with higher H2O2 concentration. This corresponds also to the measured PGE2 concentrations. CXCL8/IL8 was upregulated in all groups. Cells subjected to tension alone showed a general upregulation of osteogenic differentiation-related genes; however, pre-stimulation with OS did not induce significant changes especially towards downregulation. MAP1LC3A/LC3, BECN1 and CASP8 were generally upregulated in cells without OS pre-stimulation. Our results suggest that OS might have considerable impacts on cellular behavior during OTM.

Characteristics of HIF-1Α and HSP70 MRNA Expression, Level, and Interleukins in Experimental Chronic Generalized Periodontitis

OBJECTIVES

Periodontal diseases are a rather complex problem of modern dentistry and do not have only medical but also social significance. The objective of this study is to weigh the effect of a mixture of Thiotriazoline and L-arginine (1:4) on the parameters of the system of endogenous cytoprotection of blood and periodontal illness in rats with experimental chronic generalized periodontitis and substantiate further study of this blend.

MATERIALS AND METHODS

The study aimed to evaluate the impact of a combination of Thiotriazoline and L-arginine (in a ratio of 1:4) on the parameters of the endogenous blood cytoprotection system and periodontium in rats with experimental chronic generalized periodontitis. A group of outbred rats weighing 190-220 g and sourced from the vivarium of the Institute of Pharmacology and Toxicology of the Academy of Medical Sciences of Ukraine were divided into four groups, each consisting of 10 animals. (1) Intact group, animals that were injected intragastrically with a solution of sodium chloride to chloride 0.9% for 30 days. (2) control, animals with experimental CGP who intragastrically sodium chloride solution 0.9% for 30 days. (3) animals with experimental CGP were injected intramuscularly with Thiotriazoline + L-arginine (1:4) in a dosage of 200 mg/kg (30 days). (4) animals with experimental CGP, for which daily intragastric reference drug Mexidol, in dosage 250 mg/kg (30 days). In this study, we utilized two substances: Thiotriazoline and L-arginine hydrochloride. The combination of Thiotriazoline and L-arginine (in a ratio of 1:4) was prepared at the Department of Pharmaceutical Chemistry of ZSMU. At the conclusion of the experiment, the rats were carefully removed from the study while under thiopental-sodium anesthesia, and administered at a dosage of 40 mg/kg.

RESULTS

We have found that the administration of a combined preparation of Thiotriazoline with L-arginine to rats with CGP leads to a significant decrease in the blood concentration of pro-inflammatory cytokines IL-1b and TNF-a by 56.1% and 71%, respectively.

CONCLUSION

The administration of Mexidol at a dosage of 250 mg/kg, as well as the combination of Thiotriazoline and Larginine in a ratio of 1:4 at a dosage of 200 mg/kg, resulted in a significant reduction in gingival pocket depth in animals with CGP. Specifically, the gingival pocket depth was reduced to 6 mm (p < 0.05) with Mexidol and further reduced to 4 mm (p < 0.05) with the combination of Thiotriazoline and L-arginine. Additionally, the animals exhibited minimal bleeding, swelling, and tooth mobility when treated with the combination of Thiotriazoline and L-arginine. The administration of a combination of Thiotriazoline and L-arginine (in a ratio of 1:4) at a dosage of 200 mg/kg to animals with CGP resulted in a noteworthy reduction in the blood concentration of pro-inflammatory cytokines IL-1b and TNF-a. Specifically, there was a significant decrease of 56.1% (p < 0.05) in IL-1b and 71% (p < 0.05) in TNF-a levels. The course administration of a combination of Thiotriazoline and L-arginine (1:4) (200 mg/kg) to animals with CGP led to an increased expression of HSP70 mRNA (p < 0.05) in the periodontium by 8.2 times and HIF-1a mRNA by 8.2 times. 2.8 times (p < 0.05) against the background of an increase in the blood concentration of HSP70 by 95% (p < 0.05). Also, in the periodontium of animals in this group, a decrease in the expression of c-Fos mRNA by 36.7% (p < 0.05) was found compared to the control group.

Chemoprevention of Experimental Periodontitis in Diabetic Rats with Silk Fibroin Nanoparticles Loaded with Resveratrol

Objective: the objective of the present work is to study the effectiveness of treatment with silk fibroin nanoparticles loaded with resveratrol in experimental periodontitis in a diabetic rat model. Introduction: Periodontitis is an inflammatory pathology highly related to other diseases, such as type II diabetes. Both diseases have a specific inflammatory condition, with Interleukin (IL)-6, IL-1β and Transforming Grow Factor (TGF)-1β being the most relevant proinflammatory factors. Silk fibroin (SF) nanoparticles loaded with resveratrol (Res-SFN) are a new alternative as a treatment. Methods: 40 diabetic Sprague Dawley male rats were used and periodontitis was induced by ligation. The animals were divided into 5 treatment groups, and 1 mL of treatment was administered once a day for 4 weeks. The groups were: I: Carboxymethyl cellulose (CMC) 0.8%, II: CMC 0.8% + SF 1%, III: CMC 0.8% + RES-SFN 3 mg/mL, IV: CMC 0.8% + SF 1% + RES-SFN 3 mg/mL, V: Water. A peripheral blood sample was taken every week to quantify the inflammatory profile by ELISA (IL-6, IL-1β and TGF-1β). After 4 weeks the sacrifice was carried out and biopsies of the gum were taken. Results: Treatment with SF and RES-SFN reduced the amount of chemical inflammation mediators (with the exception of IL-1β in comparisons I-IV and II-IV (p > 0.05)), as well as the anatomopathological variables linked to it, in a significant way (p < 0.05). Conclusion: treatment with RES-SFN has reduced local inflammation in this experimental periodontitis model.

Oxidative Stress and Antioxidants in the Diagnosis and Therapy of Periodontitis

Oxidative stress has been implicated in the pathogenesis of numerous diseases. However, large interventional studies with antioxidants failed to show benefits in the prevention or treatment of cardiovascular diseases, cancer, or diabetes mellitus. Numerous clinical studies have confirmed the association of oxidative stress markers and periodontitis. Technical and biological variability is high for most of the analyzed markers and none of them seems to be optimal for routine clinical use. In a research setting, analysis of a palette of oxidative stress markers is needed to cover lipid peroxidation, protein oxidation, and the antioxidant status. The source of reactive oxygen species and their role in the pathogenesis of periodontitis remains unclear. Interventional experiments indicate that oxidative stress might be more than just a simple consequence of the inflammation. Small studies have confirmed that some antioxidants could have therapeutic value at least as an addition to the standard non-surgical treatment of periodontitis. A clear evidence for the efficiency of antioxidant treatment in large patient cohorts is lacking. Potentially, because lowering of oxidative stress markers might be a secondary effect of anti-inflammatory or antibacterial agents. As the field of research of oxidative stress in periodontitis gains attraction and the number of relevant published papers is increasing a systematic overview of the conducted observational and interventional studies is needed. This review summarizes the currently available literature linking oxidative stress and periodontitis and points toward the potential of adjuvant antioxidant treatment, especially in cases where standard treatment fails to improve the periodontal status.

Preventive Effects of Drinking Hydrogen-Rich Water on Gingival Oxidative Stress and Alveolar Bone Resorption in Rats Fed a High-Fat Diet

Obesity induces gingival oxidative stress, which is involved in the progression of alveolar bone resorption. The antioxidant effect of hydrogen-rich water may attenuate gingival oxidative stress and prevent alveolar bone resorption in cases of obesity. We examined whether hydrogen-rich water could suppress gingival oxidative stress and alveolar bone resorption in obese rats fed a high-fat diet. Male Fischer 344 rats (n = 18) were divided into three groups of six rats each: a control group (fed a regular diet and drinking distilled water) and two experimental groups (fed a high-fat diet and drinking distilled water or hydrogen-rich water). The level of 8-hydroxydeoxyguanosine was determined to evaluate oxidative stress. The bone mineral density of the alveolar bone was analyzed by micro-computerized tomography. Obese rats, induced by a high-fat diet, showed a higher gingival level of 8-hydroxydeoxyguanosine and a lower level of alveolar bone density compared to the control group. Drinking hydrogen-rich water suppressed body weight gain, lowered gingival level of 8-hydroxydeoxyguanosine, and reduced alveolar bone resorption in rats on a high-fat diet. The results indicate that hydrogen-rich water could suppress gingival oxidative stress and alveolar bone resorption by limiting obesity.