L-GLUTAMINE SUPPLEMENTATION ASSOCIATED WITH MODERATE AEROBIC TRAINING IMPROVES BIOMETRIC, GLYCEMIC PROFILE AND THE ANTIOXIDANT DEFENSE

Introduction: L-glutamine is a non-essential amino acid, whose intrinsic pool of appears to be depleted during catabolic conditions, such as intense or high duration exercise, and to avoid the exercise- related benefits. Therefore, its supplementation could provide an additional source of L-glutamine and prevent these effects. However, the oral intake of its free form has been discouraged, despites of some evidences reporting positive effects. Objective: to verify whether the L-glutamine supplementation (in its free form) could provide an additional improvement in biometric, glycemic and redox parameters, in animals undergoing moderate aerobic training (MAT). Methods: 28 Swiss male mice were divided into four groups: Cont (n=7), Ex (n=7), Glut (n=8), and Ex+Glut (n=6). Glut and Ex+Glut received gastric gavage of L-glutamine (1g/kg), while Cont and Ex groups received 100 µL of PBS one hour before exercising, five days/week, six weeks. Ex and Ex+Glut underwent moderate swimming, while Cont and Glut remained sedentary, for the same period. Mice started swimming with 2% of body weight attached to the tail during 20 min, and ended the experiment with 4% during 60 min. Results: L-glutamine supplementation increased the gastrocnemius mass and improved the glucose tolerance in animals submitted to MAT. It improved the antioxidant status in gastrocnemius, liver and pancreas, and declined it in adipose tissue in animals undergoing MAT. The drop of adipose antioxidant defense was associated with adiposity, while pancreas antioxidant activity was inversely associated with the glucose intolerance. Conclusion: L-glutamine (free form) improves biometric and glucose parameters, and enhances antioxidant activities

Resposta de choque térmico em perda auditiva induzida por ruído : efeitos da suplementação com dipeptídeos de alanil-glutamina sobre o estado das proteínas de choque térmico

Introduction: The 72 kDa heat shock protein, HSP72, located intracellularly provides cochlear cytoprotective and anti-inflammatory roles in the inner ear during stressful noise challenges. The expression of intracellular HSP72 can be potentiated by alanyl-glutamine dipeptide supplementation. Conversely, these proteins act as pro-inflammatory signals in the extracellular milieu. Objective: We explore whether noise-induced hearing loss promotes both intracellular and extracellular HSP72 heat shock response alterations, and if alanyl-glutamine dipeptide supplementation could modify heat shock response and prevent hearing loss. Methods: Female 90 day-old Wistar rats (n = 32) were randomly divided into four groups: control, noise-induced hearing loss, treated with alanyl-glutamine dipeptide and noise-induced hearing loss plus alanyl-glutamine dipeptide. Auditory brainstem responses were evaluated before noise exposure (124 dB SPL for 2 h) and 14 days after. Cochlea, nuclear cochlear complex and plasma samples were collected for the measurement of intracellular HSP72 and extracellular HSP72 by a high-sensitivity ELISA kit. Results: We found an increase in both iHSP72 and eHSP72 levels in the noise-induced hearing lossgroup, which was alleviated by alanyl-glutamine dipeptide treatment. Furthermore, H-indexof plasma/cochlea extracellular HSP72/intracellular HSP72 ratio was increased in the noise-induced hearing loss group, but prevented by alanyl-glutamine dipeptide treatment, althoughalanyl-glutamine dipeptide had no effect on auditory threshold.Conclusions: Our data indicates that cochlear damage induced by noise exposure is accompa-nied by local and systemic heat shock response markers. Also, alanyl-glutamine reduced stressmarkers even though it had no effect on noise-induced hearing loss. Finally, plasma levels of72 kDa heat shock proteins can be used as a biomarker of auditory stress after noise exposure. Além disso, alanil-glutamina reduziu os marcadores de estresse, mesmo não tendo efeito sobre a perda auditiva induzida por ruído. Finalmente, os níveis plasmáticos de proteínas de choque térmico de 72 kDa podem ser usados como biomarcador do estresse auditivo após a exposição ao ruído.Introdução: A proteína de choque térmico de 72 kDa, HSP72 localizada intracelularmente(iHSP72) possui papéis citoprotetores e anti-inflamatórios cocleares na orelha interna durante situações de ruído estressantes. A expressão dessa proteina pode ser potencializada pela suplementação com dipeptídeo de alanil-glutamina. Por outro lado, essas proteínas atuam como sinais pró-inflamatórios no meio extracelular (eHSP72). Objetivo: Investigar se a perda auditiva induzida por ruído promove alterações tanto das proteínas HSP72 intracelulares quanto extracelulares na resposta de choque térmico e se a suplementação com alanil-glutamina pode modificar a resposta de choque térmico e evitar a perda auditiva. Método: Ratos Wistar fêmeos, com 90 dias de idade (n = 32) foram divididas aleatoriamente em quatro grupos: controle, perda auditiva induzida por ruído, tratados com alanil-glutamina e perda auditiva induzida por ruído mais alanil-glutamina. Os potenciais evocados auditivos do tronco encefálico foram avaliados antes da exposição ao ruído (124 dB NPS por 2 h) e 14 dias após. A cóclea, o complexo nuclear coclear e amostras de plasma foram coletadas para mensuração de HSP72 intra e extracelular com um kit Elisa de alta sensibilidade. Resultados: Houve um aumento nos níveis de HSP72 intra e extracelular no grupo perda auditiva induzida por ruído, que foi minimizado pelo tratamento com alanil-glutamina. Além disso, o índice H das HSP72 (razão eHSP72 no plasma com alanil-glutamina, embora/cóclea) aumentou no grupo perda auditiva induzida por ruído, mas foi limitado pelo tratamento com alanil-glutamina, embora o alanil-glutamina não tenha efeito no limiar auditivo. Conclusões: Nossos dados indicam que o dano coclear induzido pela exposição ao ruído é acompanhado por marcadores da resposta de choque térmico locais e sistêmicos

Resposta de choque térmico em perda auditiva induzida por ruído : efeitos da suplementação com dipeptídeos de alanil-glutamina sobre o estado das proteínas de choque térmico

Introduction: The 72 kDa heat shock protein, HSP72, located intracellularly provides cochlear cytoprotective and anti-inflammatory roles in the inner ear during stressful noise challenges. The expression of intracellular HSP72 can be potentiated by alanyl-glutamine dipeptide supplementation. Conversely, these proteins act as pro-inflammatory signals in the extracellular milieu. Objective: We explore whether noise-induced hearing loss promotes both intracellular and extracellular HSP72 heat shock response alterations, and if alanyl-glutamine dipeptide supplementation could modify heat shock response and prevent hearing loss. Methods: Female 90 day-old Wistar rats (n = 32) were randomly divided into four groups: control, noise-induced hearing loss, treated with alanyl-glutamine dipeptide and noise-induced hearing loss plus alanyl-glutamine dipeptide. Auditory brainstem responses were evaluated before noise exposure (124 dB SPL for 2 h) and 14 days after. Cochlea, nuclear cochlear complex and plasma samples were collected for the measurement of intracellular HSP72 and extracellular HSP72 by a high-sensitivity ELISA kit. Results: We found an increase in both iHSP72 and eHSP72 levels in the noise-induced hearing lossgroup, which was alleviated by alanyl-glutamine dipeptide treatment. Furthermore, H-indexof plasma/cochlea extracellular HSP72/intracellular HSP72 ratio was increased in the noise-induced hearing loss group, but prevented by alanyl-glutamine dipeptide treatment, althoughalanyl-glutamine dipeptide had no effect on auditory threshold.Conclusions: Our data indicates that cochlear damage induced by noise exposure is accompa-nied by local and systemic heat shock response markers. Also, alanyl-glutamine reduced stressmarkers even though it had no effect on noise-induced hearing loss. Finally, plasma levels of72 kDa heat shock proteins can be used as a biomarker of auditory stress after noise exposure. Além disso, alanil-glutamina reduziu os marcadores de estresse, mesmo não tendo efeito sobre a perda auditiva induzida por ruído. Finalmente, os níveis plasmáticos de proteínas de choque térmico de 72 kDa podem ser usados como biomarcador do estresse auditivo após a exposição ao ruído.Introdução: A proteína de choque térmico de 72 kDa, HSP72 localizada intracelularmente(iHSP72) possui papéis citoprotetores e anti-inflamatórios cocleares na orelha interna durante situações de ruído estressantes. A expressão dessa proteina pode ser potencializada pela suplementação com dipeptídeo de alanil-glutamina. Por outro lado, essas proteínas atuam como sinais pró-inflamatórios no meio extracelular (eHSP72). Objetivo: Investigar se a perda auditiva induzida por ruído promove alterações tanto das proteínas HSP72 intracelulares quanto extracelulares na resposta de choque térmico e se a suplementação com alanil-glutamina pode modificar a resposta de choque térmico e evitar a perda auditiva. Método: Ratos Wistar fêmeos, com 90 dias de idade (n = 32) foram divididas aleatoriamente em quatro grupos: controle, perda auditiva induzida por ruído, tratados com alanil-glutamina e perda auditiva induzida por ruído mais alanil-glutamina. Os potenciais evocados auditivos do tronco encefálico foram avaliados antes da exposição ao ruído (124 dB NPS por 2 h) e 14 dias após. A cóclea, o complexo nuclear coclear e amostras de plasma foram coletadas para mensuração de HSP72 intra e extracelular com um kit Elisa de alta sensibilidade. Resultados: Houve um aumento nos níveis de HSP72 intra e extracelular no grupo perda auditiva induzida por ruído, que foi minimizado pelo tratamento com alanil-glutamina. Além disso, o índice H das HSP72 (razão eHSP72 no plasma com alanil-glutamina, embora/cóclea) aumentou no grupo perda auditiva induzida por ruído, mas foi limitado pelo tratamento com alanil-glutamina, embora o alanil-glutamina não tenha efeito no limiar auditivo. Conclusões: Nossos dados indicam que o dano coclear induzido pela exposição ao ruído é acompanhado por marcadores da resposta de choque térmico locais e sistêmicos

Estrogen deprivation does not affect vascular heat shock response in female rats : a comparison with oxidative stress markers

Hot flashes, which involve a tiny rise in core temperature, are the most common complaint of peri- and post-menopausal women, being tightly related to decrease in estrogen levels. On the other hand, estradiol (E2) induces the expression of HSP72, a member of the 70 kDa family of heat shock proteins (HSP70), which are cytoprotective, cardioprotective, and heat inducible. Since HSP70 expression is compromised in age-related inflammatory diseases, we argued whether the capacity of triggering a robust heat shock (HS) response would be still present after E2 withdrawal. Hence, we studied the effects of HS treatment (hot tub) in female Wistar rats subjected to bilateral ovariectomy (OVX) after a 7-day washout period. Twelve h after HS, the animals were killed and aortic arches were surgically excised for molecular analyses. The results were compared with oxidative stress markers in the plasma (superoxide dismutase, catalase, and lipoperoxidation) because HSP70 expression is also sensitive to redox regulation. Extracellular (plasma) to intracellular HSP70 ratio, an index of systemic inflammatory status, was also investigated. The results showed that HS response was preserved in OVX animals, as inferred from HSP70 expression (up to 40 % rise, p < 0.01) in the aortas, which was accompanied by no further alterations in oxidative stress, hematological parameters, and glycemic control either. This suggests that the lack of estrogen per se could not be solely ascribed as the unique source of low HSP70 expression as observed in long-term post-menopausal individuals. As a consequence, periodic evaluation of HSP70 status (iHSP70 vs. eHSP70) may be of clinical relevance because decreased HS response capacity is at the center of the onset of menopause-related dysfunctions