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.

Biochemical and Molecular Mechanisms of Glucose Uptake Stimulated by Physical Exercise in Insulin Resistance State: Role of Inflammation / Mecanismos Bioquímicos e Moleculares da Captação da Glicose Estimulada pelo Exercício Físico no Estado de Resistência à Insulina: Papel da Inflamação

Abstract Obesity associated with systemic inflammation induces insulin resistance (IR), with consequent chronic hyperglycemia. A series of reactions are involved in this process, including increased release of proinflammatory cytokines, and activation of c-Jun N-terminal kinase (JNK), nuclear factor-kappa B (NF-κB) and toll-like receptor 4 (TLR4) receptors. Among the therapeutic tools available nowadays, physical exercise (PE) has a known hypoglycemic effect explained by complex molecular mechanisms, including an increase in insulin receptor phosphorylation, in AMP-activated protein kinase (AMPK) activity, in the Ca2+/calmodulin-dependent protein kinase kinase (CaMKK) pathway, with subsequent activation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), Rac1, TBC1 domain family member 1 and 4 (TBC1D1 and TBC1D4), in addition to a variety of signaling molecules, such as GTPases, Rab and soluble N-ethylmaleimide-sensitive factor attached protein receptor (SNARE) proteins. These pathways promote greater translocation of GLUT4 and consequent glucose uptake by the skeletal muscle. Phosphoinositide-dependent kinase (PDK), atypical protein kinase C (aPKC) and some of its isoforms, such as PKC-iota/lambda also seem to play a fundamental role in the transport of glucose. In this sense, the association between autophagy and exercise has also demonstrated a relevant role in the uptake of muscle glucose. Insulin, in turn, uses a phosphoinositide 3-kinase (PI3K)-dependent mechanism, while exercise signal may be triggered by the release of calcium from the sarcoplasmic reticulum. The objective of this review is to describe the main molecular mechanisms of IR and the relationship between PE and glucose uptake.

Resumo A obesidade associada à inflamação sistêmica induz resistência à insulina (RI), com consequente hiperglicemia crônica. Este processo envolve o aumento na liberação de citocinas pró-inflamatórias, ativação da enzima c-Jun N-terminal cinase (JNK), do fator nuclear kappa-B (NF-κB) e dos receptores do tipo Toll 4 (TLR4). Dentre as ferramentas terapêuticas disponíveis, o exercício físico (EF) tem efeito hipoglicemiante conhecido, explicado por mecanismos moleculares complexos. Dentre eles, ocorre aumento na fosforilação do receptor da insulina, na atividade da proteína quinase ativada por AMP (AMPK), na via da proteína cinase cinase dependente de Ca+2/calmodulina (CaMKK), com posterior ativação do coativador-1α do receptor ativado por proliferador do peroxissoma (PGC-1α), proteínas Rac1, TBC1 membro das famílias de domínio 1 e 4 (TBC1D1 e TBC1D4), além de uma variedade de moléculas de sinalização, como as proteínas GTPases, Rab e proteína solúvel de fusão sensível a N-etil-maleimida (SNARE); estas vias promovem maior translocação de transportador de glicose do tipo 4 (GLUT4) e consequente captação de glicose pelo músculo esquelético. A cinase fosfatidilinositol-dependente (PDK), proteína quinase C atípica (aPKC) e algumas das suas isoformas, como a PKC-iota/lambda também parecem desempenhar papel fundamental no transporte de glicose. Nesse sentido, a associação entre autofagia e EF também tem demonstrado papel relevante na captação de glicose muscular. A insulina, por sua vez, utiliza um mecanismo dependente da fosfatidilinositol-3-quinase (PI3K), enquanto que o sinal do EF pode ter início mediante liberação de cálcio pelo retículo sarcoplasmático e concomitante ativação da AMPK. O objetivo desta revisão é descrever os principais mecanismos moleculares da RI e da relação entre o EF e a captação de glicose.

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 do mecanismo epigenético por metilação do DNA e da expressão de GLUT4 em tecido muscular esquelético de ratos adultos, proles de ratas com doença periodontal / Evaluation of the epigenetic mechanism by DNA methylation and GLUT4 expression in skeletal muscle tissue of adult rats, prole of rats with periodontal disease

Atualmente, está bem estabelecido que o ambiente fetal está ligado à saúde materna, e estímulos ou agressões anormais durante a vida intra-uterina podem resultar em mudanças na fisiologia e metabolismo da prole, aumentando o risco de doenças na vida adulta. Tal fenômeno é conhecido como programação fetal. Alterações na metilação do DNA e expressão gênica são consideradas mecanismos moleculares responsáveis por esta programação. Estudos anteriores demonstraram que a doença periodontal (DP) materna promove resistência insulínica, aumento nas concentrações plasmáticas de citocinas, redução do conteúdo de GLUT4 e do seu índice de translocação para membrana plasmática em sua prole adulta. E citocinas, como por exemplo, o TNF-α, têm sido relacionadas com a redução da expressão de GLUT4 por meio da ativação do fator de transcrição nuclear κappa B (NF-κB). Além disso, esta citocina pode estimular algumas serinas quinases, incluindo IκB quinase (IKK), c-Jun amino-terminal kinase (JNK) e quinases reguladas por sinais extracelulares (ERKs) que estão envolvidas na resistência insulínica. Tais achados evidenciam a necessidade de realizar mais estudos para verificar os mecanismos envolvidos nestas alterações. Portanto, os objetivos do presente estudo foram avaliar em ratos adultos, proles de ratas com DP: 1) massa corpórea ao longo de 75 dias de idade; 2) glicemia e insulinemia; 3) expressão do RNAm da proteína transportadora de glicose GLUT4 e do IRS1 em muscular esquelético gastrocnêmio (MG); 4) o grau de metilação do DNA na região promotora do gene do GLUT4 em MG; 5) fosforilação das proteínas JNK, IKKα/ß, ERK 1/2, NF-κBp65 e NF-κBp50 e seus conteúdos totais em MG; 6) conteúdo total de TNF-α em MG. As ratas foram divididas em dois grupos: 1) com doença periodontal (DP), no qual esta doença foi induzida por meio de ligadura com fio de seda ao redor do 1º molar inferior; 2) ratas controle (CN). Após 7 dias da colocação da ligadura, as ratas de ambos os grupos foram colocadas para acasalamento, verificou-se diariamente, por esfregaço vaginal, o dia da copulação. As ratas prenhas foram separadas em caixas individuais. Quando os filhotes machos destas ratas completaram 75 dias, realizaram-se os experimentos: 1) glicemia e insulinemia; 2) expressão do RNAm do GLUT4 e do IRS1 em MG; 3) o grau de metilação do DNA na região promotora do gene do GLUT4 em MG; 4) fosforilação das proteínas JNK, IKKα/ß, ERK 1/2, NF-κBp65 e NF-κBp50 e seus conteúdos totais em MG; 5) conteúdo total de TNF-α em MG. Os resultados demonstraram que a doença periodontal materna promove na sua prole adulta baixo peso ao nascimento (BPN), resistência insulínica, aumento do conteúdo total de TNF-α em MG, aumento do grau de fosforilação de IKKα/ß, ERK 1/2, NF-κBp65 (grau de fosforilação e conteúdo) e NF-κBp50 em MG, diminuição na expressão gênica da proteína transportadora de glicose GLUT4 e aumento na expressão gênica do IRS1; porém não promove nessa prole alteração no grau de metilação do DNA na região promotora do gene do GLUT4, e no grau de fosforilação da proteína JNK em MG. Portanto, este estudo é de fundamental importância para o entendimento de alguns dos mecanismos envolvidos na relação entre a doença periodontal materna e resistência à insulina na prole adulta. Além disso, mostra que a saúde bucal materna ideal pode ajudar a prevenir doenças futuras na prole adulta(AU)

It is well established that the fetal environment is linked to maternal health, and abnormal stimuli or aggressions during intrauterine life can result in changes in the physiology and metabolism of offspring, increasing the risk of disease in adult life, this phenomenon is known as fetal programming. Changes in DNA methylation and gene expression are considered molecular mechanisms responsible for this programming. Previous studies have demonstrated that maternal periodontal disease (PD) promotes insulin resistance, increased plasma concentrations of cytokines, reduced GLUT4 content and its plasma membrane translocation index in its adult offspring. And cytokines, such as TNF-α, have been linked to reduced GLUT4 expression through the activation of nuclear transcription factor kappa B (NF-κB). In addition, this cytokine can stimulate some serine kinases including IκB kinase (IKK), c-Jun amino-terminal kinase (JNK) and extracellular signal­regulated kinases (ERKs) that are involved in insulin resistance. These findings evidenced the need for further studies to verify the mechanisms involved in these changes. Therefore, the objectives of the present study were to evaluate in adult rats, offspring of rats with PD: 1) birth weight and during the 75 days of age; 2) glycemia and insulinemia; 3) GLUT4 and IRS1 mRNA expression in skeletal muscle gastrocnemius (MG); 4) the degree of DNA methylation in the promoter region of the GLUT4 gene in MG; 5) phosphorylation of JNK, IKKα/ß, ERK 1/2, NF-κBp65 and NF-κBp50 proteins and their total contents in MG; 6) TNF-α content in MG. Female Wistar rats were distributed into a control group and an experimental periodontal disease group, in which the disease is induced by ligation with silk thread around the 1st molar. Seven days after ligature placement, animals from both groups mated and daily vaginal smears were taken to verify the presence of sperm. Pregnant rats were kept in individual cages. The body weights of the offspring were measured once weekly from birth until 75 days of age. When male offspring of these rats completed 75 days, the experiments were performed: 1) glycemia and insulinemia; 2) GLUT4 and IRS1 mRNA expression in skeletal muscle gastrocnemius (MG); 3) the degree of DNA methylation in the promoter region of the GLUT4 gene in MG; 4) phosphorylation of JNK, IKKα/ß, ERK 1/2, NF-κBp65 and NF-κBp50 proteins and their total contents in MG; 5) TNF-α content in MG. The results demonstrated that maternal periodontal disease promotes in its adult offspring low birth weight (LBW), insulin resistance, increased TNF-α content in MG, increased IKKα/ß, ERK 1/2, NF-κBp65 (phosphorylation status and content) and NF-κBp50 phosphorylation status in the MG, decrease in gene expression of GLUT4 and increase in IRS1 gene expression; but does not promote in this progeny change in the degree of DNA methylation in the promoter region of the GLUT4 gene, and JNK phosphorylation status in MG. Therefore, this study is of fundamental importance for the understanding of some of the mechanisms involved in the relationship between maternal periodontal disease and insulin resistance in adult offspring. In addition, it shows that ideal maternal oral health can help prevent future illnesses in adult offspring(AU)

Skeletal muscle: from birth to old age, routes to mechanical and metabolic failure. / Músculo esquelético: del nacimiento a la vejez, rutas hacia la falla mecánica y metabólica.

Skeletal muscle (SM) is the most abundant tissue and the largest reservoir of protein in the body. It transports glucose in an insulin dependent manner by the glucose transporter type 4 (GLUT4) and contributes in the maintenance of serum amino acids concentration. By its mass and energetic requirements, it is fundamental for the systemic metabolic balance. In the present work, we present the effect of gestational undernourishment (GU) on the mechanical and metabolic properties of SM at birth and in old age in an animal model. Mechanical studies were performed on isolated muscles, while the GLUT4, amino acid transporters LAT2, SNAT2 and insulin receptors (IR) determination were performed on isolated transverse-tubule membranes (TT). The GU in offspring at birth, results in low muscle mass with increased contraction force and resistance to fatigue. However, in two-years old rats, there was muscle hypotrophy and sarcopenia, the force decreased between 50 and 70% in control rats and rats with GU respectively, accompanied by a lower expression of LAT2, SNAT2 and IR in TT. In conclusion, GU irreversibly affects the SM, an effect that could be similar in humans, which help us to understand the events that associate the GU with the metabolic debacle of SM and the metabolic diseases of human adulthood.

Maternal periodontitis decreases plasma membrane GLUT4 content in skeletal muscle of adult offspring.

AIMS: The fetal programming hypothesis suggests that intrauterine stimuli can induce metabolic changes in offspring, increasing the disease risk in adulthood. Periodontal disease may enhance serum cytokine levels. Cytokines such as tumor necrosis factor-alpha (TNF-α) have been associated with reduced glucose transporter type 4 (GLUT4) expression, decreased protein kinase B (Akt) phosphorylation, and insulin resistance. This study aimed to evaluate GLUT4 content, and Akt serine phosphorylation status in the gastrocnemius skeletal muscle (GSM), glycemia, insulinemia and change in body weight in offspring of rats with periodontal disease. MAIN METHODS: Female Wistar rats were distributed into a control group (CN) and an experimental periodontal disease group (PD), in which a ligature was placed around the mandibular first molars. Seven days after ligature placement, both groups were mated with normal male rats. The ligatures remained throughout pregnancy until weaning, after which the male offspring were distributed into groups: CN-o, control rat offspring; and PD-o, periodontal disease rat offspring. The body weight from 0 to 75days of age was measured. At 75days, the glycemia, insulinemia, TNF-α levels, Akt serine phosphorylation, and GLUT4 content in the GSM were measured in the offspring. KEY FINDINGS: The PD-o group showed a low birth weight (LBW), unchanged glycemia, increased insulinemia, insulin resistance, increased TNF-α levels, decreased Akt serine phosphorylation status, and reduced GLUT4 content in the plasma membrane and translocation index after insulin stimulation. SIGNIFICANCE: Maternal periodontal disease causes LBW, insulin resistance, and alterations in the final stage of insulin signaling in the GSM of adult offspring.

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.

Metformin improves performance in high-intensity exercise, but not anaerobic capacity in healthy male subjects.

The aim of this study was to determine the ergogenic effects of metformin in high-intensity exercise, as well as its effects on anaerobic capacity, in healthy and physically active men. Ten subjects (mean (± standard deviation) maximal oxygen uptake (V˙O2max ) 38.6 ± 4.5 mL/kg per min) performed the following tests in a cycle ergometer: (i) an incremental test; (ii) six submaximal constant workload tests at 40%-90% (V˙O2max ); and (iii) two supramaximal tests (110% (V˙O2max ). Metformin (500 mg) or placebo was ingested 60 min before the supramaximal test. There were no significant differences between the placebo and metformin groups in terms of maximum accumulated oxygen deficit (2.8 ± 0.6 vs 3.0 ± 0.8 L, respectively; P = 0.08), lactate concentrations (7.8 ± 2.6 vs 7.5 ± 3.0 mmol/L, respectively; P = 0.75) or O2 consumed in either the last 30 s of exercise (40.4 ± 4.4 vs 39.9 ± 4.0 mL/kg per min, respectively; P = 0.35) or the first 110 s of exercise (29.0 ± 2.5 vs 29.5 ± 3.0 mL/kg per min, respectively; P = 0.42). Time to exhaustion was significantly higher after metformin than placebo ingestion (191 ± 33 vs 167 ± 32 s, respectively; P = 0.001). The fast component of V˙O2 recovery was higher in the metformin than placebo group (12.71 vs 12.18 mL/kg per min, respectively; P = 0.025). Metformin improved performance and anaerobic alactic contribution during high-intensity exercise, but had no effect on overall anaerobic capacity in healthy subjects.

Avaliação da fosforilação da AKT e do conteúdo da proteína transportadora de glicose GLUT4 em tecido muscular esquelético de ratos adultos, proles de ratas com doença periodontal / Evaluation of Akt phosphorylation and glucose transporter protein 4 (GLUT4) content in gastrocnemius skeletal muscle tissue of adult rats, offspring of rats with periodontal disease

A hipótese da programação fetal sugere que estímulos ou agressões durante a vida intrauterina podem resultar em alterações permanentes na fisiologia e metabolismo da descendência, aumentando o risco de doenças na vida adulta. Estudos demonstraram que tanto a doença periodontal (DP) como o aumento do tecido adiposo elevam a concentração plasmáticas de citocinas. E citocinas, como por exemplo, o TNF-, têm sido relacionadas com a redução da expressão de GLUT4 e resistência à insulina. Sabendo que o GLUT4 é importante para homeostase glicídica, o objetivo do presente estudo foi avaliar em ratos, proles de ratas com doença periodontal ao nascimento, a massa corpórea, e na vida adulta: 1) massa corpórea ao longo de 75 dias de idade; 2) o conteúdo da proteína transportadora de glicose GLUT4 e o seu índice de translocação em tecido muscular esquelético gastrocnêmio (MG); 3) o grau de fosforilação em serina da Akt em MG. As ratas foram distribuidas em dois grupos: a) com doença periodontal (DP), no qual esta doença foi induzida por meio de ligadura com fio de seda ao redor do 1º molar inferior de ambos os lados; b) ratas controle (CN). Após 7 dias da colocação da ligadura, as ratas de ambos os grupos foram colocadas para acasalamento, verificou-se diariamente, por esfregaço vaginal, o dia da copulação. As ratas prenhas foram separadas em caixas individuais. A massa corpórea da prole foi avaliada ao nascimento e durante os 75 dias de idade. Quando os filhotes machos destas ratas completaram 75 dias, realizou-se: 1) dosagem de glicemia e insulinemia; 2) avaliação da proteína transportadora de glicose GLUT4 e seu índice de translocação em MG; 3) avaliação do grau de fosforilação em serina da Akt em MG. Os resultados demonstraram que a doença periodontal materna promove em sua prole ao nascimento baixo peso e na vida adulta: 1) nenhuma alteração nas concentrações plasmáticas de glicose; 2) aumento nas concentrações plasmáticas de insulina; 3) redução na sensibilidade..

The fetal programming hypothesis suggests that intrauterine stimuli or aggression can induce metabolic and physiology changes in offspring, increasing the diseases risk in adulthood. Studies have demonstrated that periodontal disease (PD) and adipose tissue augmentation enhance the cytokines levels. Cytokines such as TNF-α have been associated with reduced GLUT4 expression and insulin resistance. Knowing that GLUT4 is important for glucose homeostasis, the aim of present study was to evaluate in adult rats, offspring of rats with periodontal disease: 1) birth weight and during the 75 days of age; 2) GLUT4 content and its translocation index in gastrocnemius skeletal muscle tissue (GM); 3) Akt serine phosphorylation status in MG. Female Wistar rats were distributed into a control group (CN, n = 4) and a experimental periodontal disease group (PD, n = 4), in which the disease is induced by ligation with silk thread around the 1st molar. Seven days after ligature placement, animals from both groups mated and daily vaginal smears were taken to verify the presence of sperm. Pregnant rats were kept in individual cages. The body weights of the offspring were measured once weekly from birth until 75 days of age. When male offspring of these rats completed 75 days, the experiments were performed: 1) assessment of plasma concentrations of glucose and insulin; 2) evaluation of the GLUT4 content and its translocation index in GM; 3) Akt serine phosphorylation status in GM. The results showed that maternal periodontal disease causes in their offspring low birth weight, and in adulthood: 1) no changes in glycemia; 2) increase in insulinemia; 3) insulin resistance; 4) decrease in GLUT4 content in the plasma membrane and its translocation index in GM; 5) reduction in the Akt serine phosphorylation status in GM. Therefore, we can conclude that maternal periodontal disease causes low birth weight and alterations in the final stage of insulin signaling in skeletal muscle of...

Avaliação da fosforilação da AKT e do conteúdo da proteína transportadora de glicose GLUT4 em tecido muscular esquelético de ratos adultos, proles de ratas com doença periodontal / Evaluation of Akt phosphorylation and glucose transporter protein 4 (GLUT4) content in gastrocnemius skeletal muscle tissue of adult rats, offspring of rats with periodontal disease

A hipótese da programação fetal sugere que estímulos ou agressões durante a vida intrauterina podem resultar em alterações permanentes na fisiologia e metabolismo da descendência, aumentando o risco de doenças na vida adulta. Estudos demonstraram que tanto a doença periodontal (DP) como o aumento do tecido adiposo elevam a concentração plasmáticas de citocinas. E citocinas, como por exemplo, o TNF-, têm sido relacionadas com a redução da expressão de GLUT4 e resistência à insulina. Sabendo que o GLUT4 é importante para homeostase glicídica, o objetivo do presente estudo foi avaliar em ratos, proles de ratas com doença periodontal ao nascimento, a massa corpórea, e na vida adulta: 1) massa corpórea ao longo de 75 dias de idade; 2) o conteúdo da proteína transportadora de glicose GLUT4 e o seu índice de translocação em tecido muscular esquelético gastrocnêmio (MG); 3) o grau de fosforilação em serina da Akt em MG. As ratas foram distribuidas em dois grupos: a) com doença periodontal (DP), no qual esta doença foi induzida por meio de ligadura com fio de seda ao redor do 1º molar inferior de ambos os lados; b) ratas controle (CN). Após 7 dias da colocação da ligadura, as ratas de ambos os grupos foram colocadas para acasalamento, verificou-se diariamente, por esfregaço vaginal, o dia da copulação. As ratas prenhas foram separadas em caixas individuais. A massa corpórea da prole foi avaliada ao nascimento e durante os 75 dias de idade. Quando os filhotes machos destas ratas completaram 75 dias, realizou-se: 1) dosagem de glicemia e insulinemia; 2) avaliação da proteína transportadora de glicose GLUT4 e seu índice de translocação em MG; 3) avaliação do grau de fosforilação em serina da Akt em MG. Os resultados demonstraram que a doença periodontal materna promove em sua prole ao nascimento baixo peso e na vida adulta: 1) nenhuma alteração nas concentrações plasmáticas de glicose; 2) aumento nas concentrações plasmáticas de insulina; 3) redução na sensibilidade..

The fetal programming hypothesis suggests that intrauterine stimuli or aggression can induce metabolic and physiology changes in offspring, increasing the diseases risk in adulthood. Studies have demonstrated that periodontal disease (PD) and adipose tissue augmentation enhance the cytokines levels. Cytokines such as TNF-α have been associated with reduced GLUT4 expression and insulin resistance. Knowing that GLUT4 is important for glucose homeostasis, the aim of present study was to evaluate in adult rats, offspring of rats with periodontal disease: 1) birth weight and during the 75 days of age; 2) GLUT4 content and its translocation index in gastrocnemius skeletal muscle tissue (GM); 3) Akt serine phosphorylation status in MG. Female Wistar rats were distributed into a control group (CN, n = 4) and a experimental periodontal disease group (PD, n = 4), in which the disease is induced by ligation with silk thread around the 1st molar. Seven days after ligature placement, animals from both groups mated and daily vaginal smears were taken to verify the presence of sperm. Pregnant rats were kept in individual cages. The body weights of the offspring were measured once weekly from birth until 75 days of age. When male offspring of these rats completed 75 days, the experiments were performed: 1) assessment of plasma concentrations of glucose and insulin; 2) evaluation of the GLUT4 content and its translocation index in GM; 3) Akt serine phosphorylation status in GM. The results showed that maternal periodontal disease causes in their offspring low birth weight, and in adulthood: 1) no changes in glycemia; 2) increase in insulinemia; 3) insulin resistance; 4) decrease in GLUT4 content in the plasma membrane and its translocation index in GM; 5) reduction in the Akt serine phosphorylation status in GM. Therefore, we can conclude that maternal periodontal disease causes low birth weight and alterations in the final stage of insulin signaling in skeletal muscle of...

Avaliação da fosforilação da Akt e do conteúdo da proteína transportadora de glicose GLUT4 em músculo esquelético de ratos adultos com lesão periapical / Evaluation of phosphorylation of akt and content of glucose transporter protein glut4 in skeletal muscle of rats with periapical lesion

Atualmente, há certo consenso dentro da área odontológica relacionado ao fato de que inflamações crônicas nos dentes, podem eventualmente ocasionar desordens sistêmicas. A Lesão Periapical (LP) é caracterizada como uma inflamação oral e está associada ao aumento da quantidade de citocinas pró-inflamatórias, tais como, IL-6 e TNF-α, que possivelmente induzem resistência insulínica. A resistência à insulina pode ser definida como o estado no qual existe uma menor captação tecidual de glicose em resposta ao estímulo insulínico; no entanto, os mecanismos que causam resistência à insulina não são totalmente compreendidos. Estudos anteriores do nosso laboratório demonstraram que ratos adultos com LP apresentam alterações na etapa inicial da via do sinal insulínico e menor sensibilidade à insulina. Baseado nisto, mais estudos são necessários para verificar se estas alterações também estão presentes na continuidade da cascata insulínica e na expressão da proteína transportadora de glicose 4 (GLUT4). Os objetivos do presente estudo foram avaliar em ratos com LP: 1) glicemia e insulinemia (n=10); 2) sensibilidade à insulina por meio do índice de HOMA-IR (n=10); 3) grau de fosforilação em serina/treonina da Akt em tecido muscular esquelético gastrocnêmio (GM) (n=6); 4) conteúdo de GLUT4 e seu índice de translocação para membrana plasmática em GM (n=5). Para tanto, foram utilizados 32 ratos Wistar (2 meses de idade) distribuídos em dois grupos: a) ratos do grupo controle, sem a LP; b) ratos com LP induzida em molares superiores direito empregando-se broca em aço carbono dotada de esfera na extremidade com 0,1 mm. A partir dos resultados pôde-se observar que os ratos com LP apresentaram: 1) nenhuma diferença na glicemia e insulinemia; 2) redução na sensibilidade à insulina, avaliado pelo índice de HOMA-IR; 3) diminuição no grau de fosforilação em serina da Akt após estímulo insulínico em GM, mas nenhuma diferença no grau de fosforilação da Akt em treonina; 4) redução do...

Currently, there is some consensus in the dental area related to the fact that chronic inflammation in teeth may eventually lead to systemic disorders. Periapical lesion (PL) is characterized as an oral inflammation and it is associated to the increase of proinflammatory citokines, such as IL-6 and TNF-alpha, that can possibly induce insulin resistance. Insulin resistance can be defined as the state in which there is a glucose uptake decrease by tissue in response to insulin stimulation, however, the mechanisms that cause insulin resistance are not totally understood. Former studies from our laboratory demonstrated that adult rats with periapical lesion showed changes in the initial stage of insulin signaling and lower insulin sensitivity. Based on that, more studies are needed in order to verify whether these changes are also present in the continuity of the insulin signaling cascade and glucose transporter protein 4 (GLUT4) expression. The aims of this study were to evaluate in rats with PL: 1) plasma glucose and insulin levels (n=10); 2) insulin sensitivity by the HOMA-IR index (n=10); 3) serine/ threonine phosphorylation status of Akt in skeletal muscle gastrocnemius (GM) (n=6); 4) content of GLUT4 protein and its translocation index for plasma membrane in GM (n=5). Therefore, 32 Wistar rats (2 months old) were used and divided into two groups: a) control rats without PL b) rats with PL induced in right upper molars by using a carbon steel drill fitted with ball 0.1 mm. From the results it was observed that rats with PL showed: 1) no difference in blood glucose and insulin; 2) decrease in insulin sensitivity assessed by HOMA-IR index; 3) decrease in the serine phosphorylation status of Akt in GM after insulin stimulation, but no difference in the phosphorylation status of Akt in threonine; 4) decrease in the GLUT4 content in the plasma membrane, but no change in the microsome. From these results we conclude that the PL promoted insulin resistance...

Avaliação da fosforilação da Akt e do conteúdo da proteína transportadora de glicose GLUT4 em músculo esquelético de ratos adultos com lesão periapical / Evaluation of phosphorylation of akt and content of glucose transporter protein glut4 in skeletal muscle of rats with periapical lesion

Atualmente, há certo consenso dentro da área odontológica relacionado ao fato de que inflamações crônicas nos dentes, podem eventualmente ocasionar desordens sistêmicas. A Lesão Periapical (LP) é caracterizada como uma inflamação oral e está associada ao aumento da quantidade de citocinas pró-inflamatórias, tais como, IL-6 e TNF-α, que possivelmente induzem resistência insulínica. A resistência à insulina pode ser definida como o estado no qual existe uma menor captação tecidual de glicose em resposta ao estímulo insulínico; no entanto, os mecanismos que causam resistência à insulina não são totalmente compreendidos. Estudos anteriores do nosso laboratório demonstraram que ratos adultos com LP apresentam alterações na etapa inicial da via do sinal insulínico e menor sensibilidade à insulina. Baseado nisto, mais estudos são necessários para verificar se estas alterações também estão presentes na continuidade da cascata insulínica e na expressão da proteína transportadora de glicose 4 (GLUT4). Os objetivos do presente estudo foram avaliar em ratos com LP: 1) glicemia e insulinemia (n=10); 2) sensibilidade à insulina por meio do índice de HOMA-IR (n=10); 3) grau de fosforilação em serina/treonina da Akt em tecido muscular esquelético gastrocnêmio (GM) (n=6); 4) conteúdo de GLUT4 e seu índice de translocação para membrana plasmática em GM (n=5). Para tanto, foram utilizados 32 ratos Wistar (2 meses de idade) distribuídos em dois grupos: a) ratos do grupo controle, sem a LP; b) ratos com LP induzida em molares superiores direito empregando-se broca em aço carbono dotada de esfera na extremidade com 0,1 mm. A partir dos resultados pôde-se observar que os ratos com LP apresentaram: 1) nenhuma diferença na glicemia e insulinemia; 2) redução na sensibilidade à insulina, avaliado pelo índice de HOMA-IR; 3) diminuição no grau de fosforilação em serina da Akt após estímulo insulínico em GM, mas nenhuma diferença no grau de fosforilação da Akt em treonina; 4) redução do...

Currently, there is some consensus in the dental area related to the fact that chronic inflammation in teeth may eventually lead to systemic disorders. Periapical lesion (PL) is characterized as an oral inflammation and it is associated to the increase of proinflammatory citokines, such as IL-6 and TNF-alpha, that can possibly induce insulin resistance. Insulin resistance can be defined as the state in which there is a glucose uptake decrease by tissue in response to insulin stimulation, however, the mechanisms that cause insulin resistance are not totally understood. Former studies from our laboratory demonstrated that adult rats with periapical lesion showed changes in the initial stage of insulin signaling and lower insulin sensitivity. Based on that, more studies are needed in order to verify whether these changes are also present in the continuity of the insulin signaling cascade and glucose transporter protein 4 (GLUT4) expression. The aims of this study were to evaluate in rats with PL: 1) plasma glucose and insulin levels (n=10); 2) insulin sensitivity by the HOMA-IR index (n=10); 3) serine/ threonine phosphorylation status of Akt in skeletal muscle gastrocnemius (GM) (n=6); 4) content of GLUT4 protein and its translocation index for plasma membrane in GM (n=5). Therefore, 32 Wistar rats (2 months old) were used and divided into two groups: a) control rats without PL b) rats with PL induced in right upper molars by using a carbon steel drill fitted with ball 0.1 mm. From the results it was observed that rats with PL showed: 1) no difference in blood glucose and insulin; 2) decrease in insulin sensitivity assessed by HOMA-IR index; 3) decrease in the serine phosphorylation status of Akt in GM after insulin stimulation, but no difference in the phosphorylation status of Akt in threonine; 4) decrease in the GLUT4 content in the plasma membrane, but no change in the microsome. From these results we conclude that the PL promoted insulin resistance...

Aerobic exercise training induces metabolic benefits in rats with metabolic syndrome independent of dietary changes

OBJECTIVES: We evaluated the effects of aerobic exercise training without dietary changes on cardiovascular and metabolic variables and on the expression of glucose transporter Type 4 in rats with metabolic syndrome. METHODS: Twenty male spontaneously hypertensive rats received monosodium glutamate during the neonatal period. The animals were allocated to the following groups: MS (sedentary metabolic syndrome), MS-T (trained on a treadmill for 1 hour/day, 5 days/week for 10 weeks), H (sedentary spontaneously hypertensive rats) and H-T (trained spontaneously hypertensive rats). The Lee index, blood pressure (tail-cuff system), insulin sensitivity (insulin tolerance test) and functional capacity were evaluated before and after 10 weeks of training. Glucose transporter Type 4 expression was analyzed using Western blotting. The data were compared using analysis of variance (ANOVA) (p<0.05). RESULTS: At baseline, the MS rats exhibited lower insulin sensitivity and increased Lee index compared with the H rats. Training decreased the body weight and Lee index of the MS rats (MS-T vs. MS), but not of the H rats (H-T vs. H). There were no differences in food intake between the groups. At the end of the experiments, the systolic blood pressure was lower in the two trained groups than in their sedentary controls. Whole-body insulin sensitivity increased in the trained groups. Glucose transporter Type 4 content increased in the heart, white adipose tissue and gastrocnemius muscle of the trained groups relative to their respective untrained groups. CONCLUSION: In conclusion, the present study shows that an isolated aerobic exercise training intervention is an efficient means of improving several components of metabolic syndrome, that is, training reduces obesity and hypertension and increases insulin sensitivity. .