Modulatory influence of melatonin on apical periodontitis in Wistar rats fed a high-fat diet.

OBJECTIVE: This study aimed to evaluate the influence of high-fat diet (HFD) and melatonin (MEL) treatment on the progression of inflammation and alveolar bone resorption (ABR) in rats with AP. DESIGN: Forty male Wistar rats were divided into four groups: apical periodontitis (AP), HFDAP, APMEL and HFDAPMEL. The animals were fed an HFD or standard diet for 107 days. On the 7th day, the rats were subjected to AP, and after 70 days, the rats in the MEL groups were treated with MEL for 30 days. Post treatment, the animals were euthanized, and their jaws were retrieved for evaluation of bone resorption, intensity of the inflammatory response, and immunohistochemical analysis including tartrate-resistant acid phosphatase (TRAP) and interleukin-1ß (IL-1ß) levels and tumor necrosis factor (TNF)-α expression. RESULTS: The APMEL group showed reduction in the inflammatory infiltrate and IL-1ß expression relation to HFDAP, while the TNF-α levels did not differ among the groups. The HFDAP group showed an increase in the ABR. MEL reduced the TRAP levels in the APMEL and HFDAPMEL groups. CONCLUSIONS: while MEL could reduce TRAP levels in the APMEL and HFDAPMEL groups, the reduction in the HFDAPMEL group was smaller than that in the APMEL group, demonstrating that the interaction between AP and HFD decreased the anti-resorptive effects of MEL.

Melatonin decreases IRF-3 protein expression in the gastrocnemius muscle, reduces IL-1ß and LPS plasma concentrations, and improves the lipid profile in rats with apical periodontitis fed on a high-fat diet.

To evaluate the effects of melatonin (MEL) on the expression of toll-like receptor-4 (TLR4); myeloid differentiation primary response protein-88 (MyD88); TIR-domain-containing adapter-inducing interferon-ß (TRIF); IFN regulatory-factor-3 (IRF-3); nuclear factor kappa-B (NF-κB); plasma concentrations of interleukin-1ß (IL-1ß) and lipopolysaccharide (LPS); and lipid profile of rats with apical periodontitis (AP) fed on a high-fat diet (HFD). Eighty 60-day-old rats were divided into eight groups: control, AP, HFD, HFDAP, CNMEL, APMEL, HFDMEL and HFDAPMEL. HFD groups were fed on a HFD for 107 days. On day 7, experimental AP was induced in the AP groups, and after 70 days, MEL (5 mg/kg) was administered to the MEL groups for 30 days. Plasma concentrations of LPS and IL-1ß were analyzed using enzyme-linked immunosorbent assay, and the lipid profile was analyzed using biochemical tests. The expression of proteins involved in the TLR4 pathway (TLR4, MyD88, TRIF, IRF-3 and NF-κB) in the gastrocnemius muscle (GM) was evaluated using western blotting and qRT-PCR. Treatment with MEL decreased IRF-3 protein expression in GM and IL-1ß plasma concentration in the APMEL and HFDMEL groups. Reduction in LPS plasma concentration was reported only in the HFDMEL group. Additionally, a decrease in LDL and an increase in HDL were observed in the HFDMEL and HFDAPMEL groups. Treatment with MEL exhibited anti-inflammatory and anti-hyperlipidemic effects attributed to HFD and AP by reducing the plasma concentrations of IL-1ß and LPS in addition to reducing IRF-3 protein expression in the GM, which is associated with the production of inflammatory cytokines.

Melatonin decreases plasma TNF-α and improves nonenzymatic antioxidant defence and insulin sensitivity in rats with apical periodontitis fed a high-fat diet.

AIM: To analyse the effects of melatonin (ME) treatment on oxidative stress and insulin resistance (IR) in rats with apical periodontitis (AP) fed a high-fat diet (HFD). METHODOLOGY: Eighty 60-day-old rats were divided into eight groups: control (CN), AP, HFD with AP (HFDAP), control with ME (CNME), AP with ME (APME), HFD with ME (HFDME) and HFD with AP+ME (HFDAPME). The animals from the HFD groups were fed a HFD throughout the experimental period. On day 7, the animals from the AP groups were subjected to experimental AP, and after 70 days, the ME groups were treated for 30 days. Glycaemia, insulinaemia, homeostatic model assessment for IR index, tumour necrosis factor-α (TNF-α), and interleukin-6 were analysed in plasma using biochemical tests and enzyme-linked immunosorbent assay. Thiobarbituric acid-reactive substances (TBARS), carbonyl protein (CP), superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione (GSH) and total antioxidant capacity (ferric reducing antioxidant power [FRAP]) were analysed in the gastrocnemius muscle. RESULTS: (1) Association of AP and HDF exacerbated IR, and ME treatment improved this alteration; (2) AP and HFD and their association showed increased TNF-α, and ME reversed it; (3) TBARS increased in the AP and HFDAP groups, and ME reversed only in the group with the association of disease and diet; (4) CP increased in all HFD groups and improved in the ME groups; (5) GSH activity decreased in all experimental groups, and ME increased this parameter only in the CN and AP groups; (6) FRAP did not change between the groups, but ME treatment increased its activity in the AP and HFD groups; (7) ME increased SOD in the CN and AP groups. CONCLUSION: Apical periodontitis and HFD promoted IR, and the association of AP with diet promoted IR exacerbation; this resistance might have been caused by an increase in TNF-α. AP promoted more intense changes in lipid oxidative damage than in protein oxidative damage. In non-enzymatic antioxidant defence, it was observed that both AP and HFD and their association promoted a decrease in GSH levels. Overall, ME treatment reversed changes such as oxidative stress and IR.

Effect of maternal true combined endodontic-periodontal lesion on insulin and inflammatory pathway in adult offspring.

BACKGROUND: Maternal periodontal disease (PED) and apical periodontitis (AP) are associated insulin resistance (IR), increased tumor necrosis factor-α (TNF-α) levels, and alterations in insulin signaling (IS) in the gastrocnemius muscle (GM) of adult offspring. TNF-α stimulates I kappa B kinase (IKK) and c-Jun N-terminal protein kinase (JNK), resulting in IS attenuation. However, studies that investigated the maternal true endodontic-periodontal lesion (EPL) in offspring are scarce, and in this case, the impact could be even higher. This study aimed to evaluate the effects of EPL on the IR, IS, and inflammatory pathways on the offspring GM. METHODS: Female Wistar rats were distributed into control, AP, PED, and EPL groups. After 30 days of oral inflammation induction, rats from all groups were allowed to mate with healthy rats. The body weight of the offspring was assessed from birth to 75 days of age. After 75 days, the following measurements were performed: glycemia, insulinemia, IR, TNF-α content, and IKKα/ß, JNK, pp185 (Tyr), and IRS-1 (Ser) phosphorylation status in the GM. RESULTS: Maternal PED and EPL were associated with low birth weights. All maternal oral inflammations promoted IR and IS impairment in the GM and only maternal PED and EPL caused an increase in TNF-α content and IKKα/ß phosphorylation status in the GM of offspring. The offspring of the rats with EPL group showed worsening of metabolic changes when compared with offspring of rats with AP or PED. CONCLUSION: Association of maternal AP and PED promoted a more pronounced worsening in the health of the adult offspring.

Assessment of redox state and biochemical parameters of salivary glands in rats treated with anti-obesity drug sibutramine hydrochloride.

OBJECTIVES: To investigate the effects of anti-obesity drug sibutramine hydrochloride (SB) on redox state and biochemical parameters in the salivary glands. MATERIALS AND METHODS: Adult male Wistar rats were randomly divided into the following groups (n = 8 per group): control rats treated with vehicle (C) and rats treated with SB (10 mg/kg/day) by intragastric gavage for 28 days. The parotid (PG) and submandibular (SMG) glands were processed using histomorphometric analysis, and total protein, amylase, mucin, and oxidative damage to lipids were determined by measuring the formation of thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), uric acid (UA), total glutathione (tGSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), and AKT phosphorylation. RESULTS: SB decreased the acinar area, and increased the stromal area in PG, while no effect on the morphometric parameters was observed in SMG. SB also increased oxidative damage to lipids (TBARs). The SB group showed lower total protein, amylase, TAC, UA, tGSH, SOD, CAT, and GPx than the C group in PG, while in SMG, SB decreased total protein, mucin, tGSH, SOD, CAT, and GPx. However, increased AKT phosphorylation observed in both salivary glands suggests that SB exerts low-intensity oxidative stress. CONCLUSIONS: SB impaired enzymatic and non-enzymatic antioxidant defenses in the salivary glands of rats. CLINICAL RELEVANCE: Chronic treatment with SB could mitigate salivary gland dysfunction due to disturbance of redox state.

Effect of resistance training on osteopenic rat bones in neonatal streptozotocin-induced diabetes: Analysis of GLUT4 content and biochemical, biomechanical, densitometric, and microstructural evaluation.

AIMS: To investigate the effect of resistance training-RT on glycemia, expression of the glucose transporter-GLUT4, bone mineral density-BMD, and microstructural and biomechanical properties of osteopenic rat bones in neonatal streptozotocin-induced diabetes. MAIN METHODS: Sixty-four 5-day-old male rats were divided into two groups: control and diabetic rats injected with vehicle or streptozotocin, respectively. After 55 days, densitometric analysis-DA of the tibia was performed. These groups were subdivided into four subgroups: non-osteopenic control-CN, osteopenic control-OC, non-osteopenic diabetic-DM, and osteopenic diabetic-OD. The OC and OD groups were suspended by their tails for 21 days to promote osteopenia in the hindlimb; subsequently, a second DA was performed. The rats were subdivided into eight subgroups: sedentary control-SC, sedentary osteopenic control-SOC, exercised control-EC, exercised osteopenic control-EOC, sedentary diabetic-SD, sedentary osteopenic diabetic-SOD, exercised diabetic-ED, and exercised osteopenic diabetic-EOD. For RT, the rats climbed a ladder with weights secured to their tails for 12 weeks. After RT, a third DA was performed, and blood samples, muscles, and tibias were assessed to measure glycemia, insulinemia, GLUT4 content, bone maximum strength, fracture energy, extrinsic stiffness, BMD, cancellous bone area, trabecular number, and trabecular width. KEY FINDINGS: After RT, glycemia, GLUT4 content, BMD, and bone microstructural and biomechanical properties were improved in diabetic rats (osteopenic and non-osteopenic). However, RT had no effect on these parameters in the EC and SC groups. SIGNIFICANCE: These results suggest that RT improves GLUT4 content, BMD, and microstructural and biomechanical properties of bone in osteopenic and non-osteopenic diabetic rats and is effective in controlling glycemia.

Effect of maternal apical periodontitis on the final step of insulin signalling and inflammatory pathway in the adult male offspring of rats.

AIM: To evaluate the final step of insulin signalling, inflammatory pathway (related to the inhibition of insulin signalling), peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) protein content and DNA methylation in the Slc2a4 gene promoter region in the skeletal muscle of adult male offspring of rats with apical periodontitis (AP) in a single tooth or in four teeth. METHODOLOGY: Female Wistar rats were distributed into three groups: a control group, a group with one tooth with AP and a group with four teeth with AP. Thirty days after induction of AP, female rats from all groups were mated with healthy male rats. When male offspring reached 75 days of age, the following analyses were performed in the gastrocnemius muscle (GM): insulin-stimulated Akt serine and threonine phosphorylation status; NF-κB p50 and p65 subunits phosphorylation status; GLUT4, TNF-α and PGC-1α protein content by Western blotting; GLUT4 and TNF-α gene expression by real-time polymerase chain reaction (PCR); and DNA methylation in the Slc2a4 gene promoter region by restriction digestion and real-time PCR. Analysis of variance was performed, followed by Tukey's post hoc test. p values <.05 were considered to be statistically significant. RESULTS: Maternal AP in four teeth decreased insulin-stimulated Akt serine and threonine phosphorylation status, reduced GLUT4 gene expression and its protein content, and increased NF-κB p50 and p65 subunits phosphorylation status in the GM of adult offspring. There were no alterations in the parameters analysed in the GM of adult offspring of rats with AP in a single tooth. In addition, maternal AP did not affect TNF-α gene expression and its protein content, PGC-1α protein content and DNA methylation in the Slc2a4 gene promoter region in the GM of adult offspring. CONCLUSIONS: Maternal AP in four teeth was associated with impairment in the final step of insulin signalling in the GM of adult male offspring in rats. An increase in NF-κB activity may be involved in this decrease in insulin signalling. This study demonstrates the impact of maternal AP on the health of offspring, demonstrating the importance of maintaining adequate maternal oral health to prevent diseases in adult offspring in rats.

Maternal Apical Periodontitis Increases Insulin Resistance and Modulates the Antioxidant Defense System in the Gastrocnemius Muscle of Adult Offspring.

INTRODUCTION: Maternal apical periodontitis (AP) is associated with insulin resistance (IR) in adult offspring. Oxidative stress has been linked to IR. This study investigated insulin sensitivity (IS) and oxidative stress in the gastrocnemius muscle (GM) of adult offspring of rats with AP. METHODS: Fifteen female Wistar rats were distributed into a control group, a group with 1 tooth with AP, and a group with 4 teeth with AP. Thirty days after AP induction, female rats were mated with healthy male rats. When male offspring reached 75 days of age, glycemia, insulinemia, and IS were determined. In the GM, the oxidative damage products (thiobarbituric acid reactive substances and carbonyl protein) and activities of enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) and nonenzymatic (glutathione and total antioxidant capacity) antioxidants were quantified. Analysis of variance was performed followed by the Tukey post hoc test (P < .05). RESULTS: Maternal AP was associated with decreased IS and changes in antioxidant activities (reduced superoxide dismutase and increased catalase, glutathione peroxidase, and glutathione) and decreased thiobarbituric acid reactive substance concentration in the GM of their adult offspring. However, maternal AP does not appear to affect glycemia, carbonyl protein concentration, and the nonenzymatic total antioxidant capacity in the GM of this offspring. CONCLUSIONS: Maternal AP modulates the antioxidant defense system in the GM of their adult offspring, attenuating lipid peroxidation in this tissue. This reflects part of an adaptive response of the offspring to the stimulation of the maternal chronic oral inflammatory process in which the organism acts by decreasing oxidative tissue damage in the postnatal stage. The present study improves knowledge about the impact of maternal oral inflammation on healthy offspring.

Effect of maternal periodontitis on GLUT4 and inflammatory pathway in adult offspring.

BACKGROUND: Maternal periodontal disease leads to low birth weight (LBW), insulin resistance (IR), increased TNF-α levels, and alterations in insulin signaling in adult offspring. TNF-α has been associated with the stimulation of IKKß/NF-κB, resulting in the decreased expression of GLUT4. Another mechanism that may be involved in decreasing GLUT4 expression is DNA methylation. This study aimed to evaluate in the adult offspring of rats with periodontal disease: IR, inflammatory pathways, DNA methylation, and expression of GLUT4. METHODS: Female Wistar rats were distributed into control and experimental periodontal disease groups. Seven days after induction of periodontal disease, both groups were mated with healthy male rats. After weaning, male offspring were distributed into control offspring (CN-o) and periodontal disease offspring (PED-o) groups. Body weights were measured from 0-75 days of age. At day 75, the following were measured in the offspring: IR (HOMA-IR index); TNF-α and NF-κBp65 content in the gastrocnemius muscle (GM) by western blotting; IKKα/ß, JNK, ERK 1/2, NF-κBp65, and NF-κBp50 phosphorylation status in the GM by western blotting; DNA methylation by restriction digest and real-time PCR(qAMP); and expression of GLUT4 mRNA in the GM by real-time PCR. RESULTS: LBW, IR, increases in TNF-α, IKKα/ß, ERK 1/2, NF-κBp65, and NF-κBp50 decreased expression of GLUT4 mRNA were observed in the PED-o rats. No differences were identified in JNK phosphorylation status and DNA methylation in the evaluated regions of the GLUT4-encoding gene Slc2a4. CONCLUSION: Maternal periodontal disease causes LBW, IR, activation of inflammatory pathways, and decreased GLUT4 expression in the GM of adult offspring.

Avaliação das vias insulínica e inflamatória em tecidos muscular esquelético e adiposo de ratos adultos, proles de ratas com lesão periapical / Assessment of insulin signaling and inflammatory pathways in skeletal muscle and adipose tissues of adult rats, offspring of the rats with periapical lesion

A programação fetal sugere que estímulos adversos quando aplicados durante o início do desenvolvimento fetal podem alterar o metabolismo da prole, aumentando o risco de doenças na sua vida adulta. Estudos demonstraram que a doença periodontal materna em ratas promove resistência insulínica (RI) em sua prole adulta. Entretanto, estudos que investigaram os efeitos da lesão periapical (LP) materna sobre a saúde da prole são escassos. A LP é uma inflamação no ápice da raiz dental ocasionada geralmente a partir de infecção por bactérias advindas do sistema de canal radicular. Esta patologia está associada com o aumento de fator de necrose tumoral-alfa (TNF-α) que pode estimular quinase do inibidor kappa B (IKK) e c-Jun amino-terminal quinase (JNK), as quais promovem a fosforilação do substrato do receptor de insulina 1 (IRS-1) em resíduos de serina, resultando na atenuação do sinal insulínico (SI), contribuindo com a RI. Nesse contexto, tornou-se fundamental investigar se a LP materna também promove RI em sua prole adulta. Em vista disso, os objetivos deste estudo foram avaliar os efeitos da LP materna em ratas sobre as concentrações plasmáticas de glicose, insulina e TNF-α, sensibilidade à insulina e as vias insulínica e inflamatória no músculo gastrocnêmio (MG) e tecido adiposo branco periepididimal (TABp) de sua prole adulta. Para tanto, as 15 ratas Wistar (2 meses de idade) foram distribuídas em 3 grupos: 1) ratas controle; 2) ratas com uma LP induzida em primeiro molar superior direito; 3) ratas com quatro LPs induzidas em primeiros e segundos molares superiores e inferiores do lado direito. A LP foi induzida empregando-se broca em aço carbono dotada de esfera de 0,1 mm na extremidade. Após 30 dias de exposição pulpar, as ratas de todos os grupos foram colocadas para acasalamento com ratos saudáveis. Quando os filhotes machos de todas as ratas completaram 75 dias de idade, realizaram-se os seguintes experimentos: 1) dosagem de glicemia e insulinemia, seguido pelo cálculo do Modelo de Avaliação da Homeostase da Resistência à Insulina (HOMA-IR); 2) análise da concentração plasmática de TNF-α pelo método de ensaio de imunoabsorção enzimática e 3) avaliação do grau de fosforilação em tirosina da pp185, do grau de fosforilação em serina do IRS-1 e do grau de fosforilação de IKKα/ß e JNK no MG e TABp pelo método de Western blotting. A análise estatística foi feita por análise de variância, seguida pelo teste de Tukey (p<0,05). Os resultados demonstraram que a LP materna promove em sua prole adulta: 1) RI; 2) prejuízo na transdução da etapa inicial do SI no MG e TABp; 3) aumento nas concentrações plasmáticas de insulina e TNF-α; 4) maior grau de fosforilação de IKKα/ß no MG e TABp; 4) inalteração na glicemia de jejum; 5) nenhuma mudança no grau de fosforilação de JNK no MG e TABp. Esses resultados demonstram que a LP materna está associada a RI e promove importantes alterações nas vias de SI e inflamação na vida adulta de sua prole. Isso reforça a importância que a manutenção da saúde bucal materna tem sobre a saúde geral da prole(AU)

Fetal programming suggests that adverse stimuli applied during early fetal development can alter metabolism of the offspring, increasing the risk of disease in adulthood. Studies have shown that maternal periodontal disease in rats promotes insulin resistance (IR) in their adult offspring. However, there is a scarcity of research that investigated the relationship between maternal periapical lesion (PL) and health of offspring. PL is inflammatory process around the apex of a tooth root, caused by bacterial infection of the pulp and root canal system. This pathology is associated with increased tumor necrosis factor-alpha (TNF-α) which may stimulate inhibitor of kappa B kinase (IKK) and c-Jun amino-terminal kinase (JNK), which promote phosphorylation of substrate insulin receptor 1 (IRS-1) on serine residues, resulting in insulin signal (IS) attenuation, contributing to IR. In this context, it has become essential to investigate whether maternal PL also promotes IR in their offspring. This study aimed to investigate the effects of maternal PL in rats on plasma concentrations of glucose, insulin and TNF-α, insulin sensivity and the insulin and inflammatory signaling pathways in gastrocnemius muscle (GM) and periepididimal white adipose tissue (pWAT) of their adult offspring. Fifteen female Wistar rats (2 months old) were distributed in 3 groups: 1) control rats; 2) rats with 1 PL, which was induced in the right maxillary first molar; 3) rats with 4 PL, which were induced in the right upper and lower first and second molars. PL was induced using a surgical round bur 0.1 mm diameter. After 30 days of pulp exposure, female rats of all groups were mated with normal male rats. When the male offspring of rats of all rats reached 75 days old, the experiments were performed: 1) measures of glycemia and insulinemia, followed by Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), 2) analysis of plasma concentration of TNF-α by enzyme-linked immunosorbent assay method, and 3) evaluation of the pp185 tyrosine, IRS-1 serine, IKKα/ß and JNK phosphorylation status in GM and pWAT by western blot method. Statistical analysis was performed by analysis of variance, followed by Tukey post hoc test (p<0.05). The results showed that maternal PL promotes in its adult offspring: 1) IR, 2) impairment in the transduction of the initial steps of IS in the GM and pWAT, 3) increased plasma concentrations of insulin and TNF-α, 4) greater IKKα/ß phosphorylation status in GM and pWAT, 4) unchanged fasting glycemia; 5) no change in the JNK phosphorylation status in GM and pWAT. These results demonstrate that maternal PL is associated with IR and promotes important alterations in IS and inflammation pathways in adult offspring. This reinforces the importance that the maintenance of maternal oral health has on the general health of offspring(AU)

Melatonin promotes reduction in TNF levels and improves the lipid profile and insulin sensitivity in pinealectomized rats with periodontal disease.

AIM: This study aimed to investigate the effects of melatonin (ME) on insulin resistance (IR) and signaling (IS), proinflammatory cytokine levels, and lipid profiles in pinealectomyzed (PNX) rats with periodontal disease (PD). MAIN METHODS: One hundred and forty-four rats (age = 40 days) were distributed into 8 groups: 1) control (CN); 2) PD only; 3) PNX only; 4) PNX and PD (PNXPD); 5) CN treated with ME (CNM); 6) PD treated with ME (PDM); 7) PNX treated with ME(PNXM); 8) PNX and PD treated with ME(PNXPDM). The PNX groups were subjected to pinealectomy at 40 and at 60 days of age. The animals were then subjected to PD induction in the mandibular first molars. After PD induction, the ME replacement therapy (MERT-5 mg/kg body weight) was performed using water for 28 days. After this period, the plasma concentration of glucose, insulin, TNF, IL-6, triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol, and VLDL-cholesterol and the HOMA-IR index were determined. Akt serine phosphorylation status in the white adipose tissue, gastrocnemius muscle, and rat liver were also evaluated. KEY FINDINGS: PD, PNX, and PNXPD groups showed an increase in IR with elevated plasma levels of insulin and TNF compared to CN group. PNX and PNXPD groups presented alteration in lipid profile compared to CN group. MERT improved all of the analyzed parameters. No difference was observed in the IS among different groups. SIGNIFICANCE: The results suggest that MERT efficiently prevents IR, improves lipid profile, and increases plasma levels of insulin and TNF in PD and PNX rats.

Periapical Lesions Increase Macrophage Infiltration and Inflammatory Signaling in Muscle Tissue of Rats.

INTRODUCTION: Our previous studies have shown that periapical lesions (PLs) in rats cause systemic disorders such as increased tumor necrosis factor-α plasma levels, insulin resistance, and impairment in insulin signal transduction in muscle tissue. However, the mechanisms involved in these alterations are not fully understood. Under chronic inflammatory conditions such as obesity, it has been shown that the skeletal muscle is affected by inflammation, and the number of resident macrophages that are associated with impairments of insulin action and sensitivity is increased. This study aimed to investigate the presence of macrophages, activation of inflammatory pathways in muscle tissue, glycemia, and insulinemia of rats with PLs. METHODS: Sixty Wistar rats were distributed into a control group; a group with 1 PL (1PL), which was induced in the right maxillary first molar; and a group with 4 PLs (4PL), which were induced in the right upper and lower first and second molars. We quantified macrophage content by immunohistochemistry for the F4/80 protein. We evaluated Jun N-terminal kinase and IKKα/ß phosphorylation status in the muscle tissue by Western blotting. Serum levels of lipopolysaccharide (LPS) and HSP70 and plasma levels of glucose and insulin were assessed by using commercial kits. RESULTS: The 1PL and 4PL groups showed increase in macrophage content, IKKα/ß, and Jun N-terminal kinase phosphorylation status, serum LPS and HSP70 levels, and insulin resistance and no changes in glycemia and insulinemia compared with the control group. There was no difference in these parameters between the 1PL and 4PL groups. CONCLUSIONS: PLs promoted an increase in macrophage infiltration, activation of inflammatory pathways in muscle tissue, and serum concentrations of HSP70 and LPS in rats. The present study improves the knowledge on the impact of oral inflammations on the development of systemic alteration, which can induce insulin resistance.

Effects of fluoride on insulin signaling and bone metabolism in ovariectomized rats.

Fluoride is an essential trace element for the maintenance of bone health owing to its capacity to stimulate proliferation and osteoblastic activity that can lead to increased bone formation. However, excessive sodium fluoride (NaF) intake can impair carbohydrate metabolism thereby promoting hyperglycemia, insulin resistance, and changes in insulin signaling. Thus, this study aimed to evaluate the effect of chronic treatment with NaF in bone metabolism, insulin signaling, and plasma concentrations of glucose, insulin, tumor necrosis factor-α (TNF-α), osteocalcin (OCN), and fluoride in ovariectomized rats. Thirty-two ovariectomized Wistar rats were randomly distributed into two groups: Control (OVX-C) and those undergoing treatment with NaF (50mg F/L) in drinking water for 42days (OVX-F). Glucose and insulin levels were assessed, followed by homeostasis model assessment of insulin resistance (HOMA-IR). Akt serine phosphorylation was evaluated by western blotting. Plasma concentrations of TNF-α and OCN were evaluated by ELISA. The left and right tibia was collected for immunohistochemical and histomorphometric analysis, respectively. Chronic treatment with NaF promoted insulin resistance, decreased insulin signal, increased plasma concentration of insulin, fluoride, OCN and TNF-α, decreased trabecular bone area of the tibia, and caused changes in bone metabolism markers in ovariectomized rats. These results suggest the need for caution in the use of NaF for the treatment of osteoporosis, especially in postmenopausal woman.

Periapical lesions decrease Akt serine phosphorylation and plasma membrane GLUT4 content in rat skeletal muscle.

OBJECTIVES: Periapical lesion (PL) promotes insulin resistance; however, the mechanisms underlying this alteration are not fully understood. Therefore, in this study, we aimed to evaluate the Akt serine phosphorylation status and GLUT4 expression levels in the gastrocnemius muscle (GM) of rats with PL. MATERIALS AND METHODS: Male Wistar rats (n = 42) were distributed equally into control (CN) and PL groups. The pulpal tissue of the PL group rats was exposed to the oral environment for 30 days. Thereafter, glucose and insulin levels were assessed, followed by homeostasis model assessment of insulin resistance (HOMA-IR). The Akt serine phosphorylation and GLUT4 levels of microsomal (M) and plasma membrane (PM) fractions were evaluated by western blotting and analyzed statistically. RESULTS: Compared to CN group rats, PL group rats had lower insulin sensitivity (as observed by HOMA-IR), lower Akt serine phosphorylation status after insulin stimulus, and lower GLUT4 levels in the PM fraction. However, the M fraction in the PL group did not differ significantly from that of the CN group. CONCLUSIONS: PL decreases insulin sensitivity, Akt phosphorylation, and PM GLUT4 content. CLINICAL RELEVANCE: The present study indicates that preventing endodontic disease can thwart insulin resistance.