1
|
Basilio PG, Oliveira APCD, Castro ACFD, Carvalho MRD, Zagatto AM, Martinez PF, Okoshi MP, Okoshi K, Ota GE, Reis FAD, Oliveira-Junior SAD. Intermittent Fasting Attenuates Exercise Training-Induced Cardiac Remodeling. Arq Bras Cardiol 2020; 115:184-193. [PMID: 32876182 PMCID: PMC8384291 DOI: 10.36660/abc.20190349] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/14/2019] [Indexed: 12/22/2022] Open
Abstract
Fundamento A influência de intervenções não farmacológicas como restrição calórica e exercício físico sobre a saúde e prevenção de enfermidades cardíacas tem sido documentada em estudos clínicos e experimentais. Objetivo Analisar a influência da combinação entre dieta intermitente e exercício físico sobre a capacidade funcional, metabolismo glicêmico e remodelação cardíaca. Métodos Foram utilizados 60 ratos Wistar machos distribuídos em quatro grupos: Controle (C), Exercício Físico (EF), Dieta Intermitente (DI) e Exercício Físico e Dieta Intermitente (EDI). Durante 12 semanas, enquanto C e EF foram tratados diariamente com dieta comercial padrão ad libitum, DI e EDI receberam dieta similar em dias alternados com dias de jejum. Os grupos EF e EDI foram submetidos a protocolo de corrida em esteira rolante. Posteriormente, foram analisadas capacidade funcional, comportamento nutricional e metabolismo glicêmico. Além da morfologia do coração, a expressão proteica das proteínas extracellular signal-regulated kinase (ERK) e c-Jun N-terminal kinase (JNK) no coração foi avaliada por Western-blot. A análise dos resultados foi feita por meio de Two-Way ANOVA e teste de Student-Newman-Keuls. O nível de significância considerado foi de 5%. Resultados O exercício físico aumentou a capacidade funcional nos grupos EF e EDI, e acarretou fibrose cardíaca. A combinação entre dieta intermitente e exercício físico resultou em menor área sob a curva de glicemia e menores medidas de área e interstício cardíaco no EDI em relação ao EF. A expressão de proteínas ERK e JNK foi similar entre os grupos (p>0,05). Conclusões Dieta intermitente se associa com melhor tolerância glicêmica e atenua o processo de remodelação cardíaca decorrente do exercício físico. (Arq Bras Cardiol. 2020; 115(2):184-193)
Collapse
Affiliation(s)
- Priscilla Gois Basilio
- Laboratório de Estudo do Músculo Estriado (LEME/INISA), Universidade Federal de Mato Grosso do Sul,Campo Grande, MS - Brasil
| | - Ana Priscila Cayres de Oliveira
- Laboratório de Estudo do Músculo Estriado (LEME/INISA), Universidade Federal de Mato Grosso do Sul,Campo Grande, MS - Brasil
| | - Ana Carolini Ferreira de Castro
- Laboratório de Estudo do Músculo Estriado (LEME/INISA), Universidade Federal de Mato Grosso do Sul,Campo Grande, MS - Brasil
| | - Marianna Rabelo de Carvalho
- Laboratório de Estudo do Músculo Estriado (LEME/INISA), Universidade Federal de Mato Grosso do Sul,Campo Grande, MS - Brasil
| | - Alessandro Moura Zagatto
- Departamento de Educação Física, Laboratório de Fisiologia e Desempenho Esportivo (LAFIDE), Faculdade de Ciências - Universidade Estadual Paulista (UNESP),Bauru, SP - Brasil
| | - Paula Felippe Martinez
- Laboratório de Estudo do Músculo Estriado (LEME/INISA), Universidade Federal de Mato Grosso do Sul,Campo Grande, MS - Brasil
| | - Marina Politi Okoshi
- Faculdade de Medicina de Botucatu - Departamento de Clínica Médica - Universidade Estadual Paulista (UNESP),Botucatu, SP - Brasil
| | - Katashi Okoshi
- Departamento de Educação Física, Laboratório de Fisiologia e Desempenho Esportivo (LAFIDE), Faculdade de Ciências - Universidade Estadual Paulista (UNESP),Bauru, SP - Brasil
| | - Gabriel Elias Ota
- Laboratório de Estudo do Músculo Estriado (LEME/INISA), Universidade Federal de Mato Grosso do Sul,Campo Grande, MS - Brasil
| | | | - Silvio Assis de Oliveira-Junior
- Laboratório de Estudo do Músculo Estriado (LEME/INISA), Universidade Federal de Mato Grosso do Sul,Campo Grande, MS - Brasil
| |
Collapse
|
2
|
Deus AFD, Silva VLD, de Souza SLB, Mota GAF, Sant'Ana PG, Vileigas DF, Lima-Leopoldo AP, Leopoldo AS, Campos DHSD, de Tomasi LC, Padovani CR, Kolwicz SC, Cicogna AC. Myocardial Dysfunction after Severe Food Restriction Is Linked to Changes in the Calcium-Handling Properties in Rats. Nutrients 2019; 11:nu11091985. [PMID: 31443528 PMCID: PMC6770438 DOI: 10.3390/nu11091985] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/09/2019] [Accepted: 08/14/2019] [Indexed: 12/13/2022] Open
Abstract
Severe food restriction (FR) impairs cardiac performance, although the causative mechanisms remain elusive. Since proteins associated with calcium handling may contribute to cardiac dysfunction, this study aimed to evaluate whether severe FR results in alterations in the expression and activity of Ca2+-handling proteins that contribute to impaired myocardial performance. Male 60-day-old Wistar–Kyoto rats were fed a control or restricted diet (50% reduction in the food consumed by the control group) for 90 days. Body weight, body fat pads, adiposity index, as well as the weights of the soleus muscle and lung, were obtained. Cardiac remodeling was assessed by morphological measures. The myocardial contractile performance was analyzed in isolated papillary muscles during the administration of extracellular Ca2+ and in the absence or presence of a sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) specific blocker. The expression of Ca2+-handling regulatory proteins was analyzed via Western Blot. Severe FR resulted in a 50% decrease in body weight and adiposity measures. Cardiac morphometry was substantially altered, as heart weights were nearly twofold lower in FR rats. Papillary muscles isolated from FR hearts displayed mechanical dysfunction, including decreased developed tension and reduced contractility and relaxation. The administration of a SERCA2a blocker led to further decrements in contractile function in FR hearts, suggesting impaired SERCA2a activity. Moreover, the FR rats presented a lower expression of L-type Ca2+ channels. Therefore, myocardial dysfunction induced by severe food restriction is associated with changes in the calcium-handling properties in rats.
Collapse
Affiliation(s)
- Adriana Fernandes de Deus
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University, Botucatu 18618687, Brazil
| | - Vítor Loureiro da Silva
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University, Botucatu 18618687, Brazil
| | - Sérgio Luiz Borges de Souza
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University, Botucatu 18618687, Brazil
| | | | - Paula Grippa Sant'Ana
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University, Botucatu 18618687, Brazil
| | - Danielle Fernandes Vileigas
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University, Botucatu 18618687, Brazil
| | - Ana Paula Lima-Leopoldo
- Department of Sports, Center of Physical Education and Sports, Federal University of Espírito Santo, Vitória 29075-910, Brazil
| | - André Soares Leopoldo
- Department of Sports, Center of Physical Education and Sports, Federal University of Espírito Santo, Vitória 29075-910, Brazil
| | | | - Loreta Casquel de Tomasi
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University, Botucatu 18618687, Brazil
| | - Carlos Roberto Padovani
- Department of Biostatistics, Institute of Biosciences, São Paulo State University, Botucatu 18618970, Brazil
| | - Stephen C Kolwicz
- Department of Health and Exercise Physiology, Ursinus College, Collegeville, PA 19426, USA
| | - Antonio Carlos Cicogna
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University, Botucatu 18618687, Brazil.
| |
Collapse
|
3
|
Okoshi MP, Cezar MDM, Iyomasa RM, Silva MB, Costa LCO, Martinez PF, Campos DHS, Damatto RL, Minicucci MF, Cicogna AC, Okoshi K. Effects of early aldosterone antagonism on cardiac remodeling in rats with aortic stenosis-induced pressure overload. Int J Cardiol 2016; 222:569-575. [PMID: 27513653 DOI: 10.1016/j.ijcard.2016.07.266] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/29/2016] [Accepted: 07/30/2016] [Indexed: 11/17/2022]
Abstract
UNLABELLED Aldosterone plays a pivotal role in the pathophysiology of systolic heart failure. However, whether early aldosterone antagonism improves cardiac remodeling during persistent pressure overload is unsettled. We evaluated the effects of aldosterone antagonist spironolactone on cardiac remodeling in rats with ascending aortic stenosis (AS). METHODS Three days after inducing AS, weaning rats were randomized to receive spironolactone (AS-SPR, 20mg/kg/day) or no drug (AS) for 18weeks, and compared with sham-operated rats. Myocardial function was studied in isolated left ventricular (LV) papillary muscles. STATISTICAL ANALYSES ANOVA or Kruskal-Wallis tests. RESULTS Echocardiogram showed that LV diastolic (Sham 8.73±0.57; AS 8.30±1.10; AS-SPR 9.19±1.15mm) and systolic (Sham 4.57±0.67; AS 3.61±1.49; AS-SPR 4.62±1.48mm) diameters, left atrial diameter (Sham 5.80±0.44; AS 7.15±1.22; AS-SPR 8.02±1.17mm), and LV mass were higher in AS-SPR than AS. Posterior wall shortening velocity (Sham 38.5±3.8; AS 35.6±5.6; AS-SPR 31.1±3.8mm/s) was lower in AS-SPR than Sham and AS; E/A ratio was higher in AS-SPR than Sham. Developed tension was lower in AS and AS-SPR than Sham. Time to peak tension was higher in AS-SPR than Sham and AS after post-rest contraction. Right ventricle weight was higher in AS-SPR than AS, suggesting more severe heart failure in AS-SPR than AS. Interstitial collagen fractional area and myocardial hydroxyproline concentration were higher in AS than Sham. Metalloproteinase-2 and -9 activity, evaluated by zymography, did not differ between groups. CONCLUSION Early spironolactone administration causes further hypertrophy in cardiac chambers, and left ventricular dilation and dysfunction in rats with AS-induced chronic pressure overload.
Collapse
Affiliation(s)
- M P Okoshi
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil.
| | - M D M Cezar
- Itapeva Social and Agrarian Sciences College, FAIT, Itapeva, SP, Brazil
| | - R M Iyomasa
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil
| | - M B Silva
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil
| | - L C O Costa
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil
| | - P F Martinez
- Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - D H S Campos
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil
| | - R L Damatto
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil; Itapeva Social and Agrarian Sciences College, FAIT, Itapeva, SP, Brazil
| | - M F Minicucci
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil
| | - A C Cicogna
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil
| | - K Okoshi
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Brazil
| |
Collapse
|
4
|
Guizoni DM, Oliveira-Junior SA, Noor SLR, Pagan LU, Martinez PF, Lima ARR, Gomes MJ, Damatto RL, Cezar MDM, Bonomo C, Zornoff LAM, Okoshi K, Okoshi MP. Effects of late exercise on cardiac remodeling and myocardial calcium handling proteins in rats with moderate and large size myocardial infarction. Int J Cardiol 2016; 221:406-12. [PMID: 27404715 DOI: 10.1016/j.ijcard.2016.07.072] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/04/2016] [Indexed: 01/10/2023]
Abstract
BACKGROUND Physical exercise attenuates myocardial infarction (MI)-induced cardiac remodeling. However, it is unsettled whether late exercise modulates post-infarction cardiac remodeling differentially according to infarct size. We investigated the effects of exercise started at late stage heart failure on cardiac remodeling in rats with moderate and large sized MI. METHODS Three months after MI, rats were assigned into sedentary and exercise groups. Exercise rats underwent treadmill for three months. After assessing infarct size by histological analysis, rats were subdivided into four groups: moderate MI sedentary (Mod MI-Sed; n=7), Mod MI exercised (Mod MI-Ex; n=7), Large MI-Sed (n=11), and Large MI-Ex (n=10). RESULTS Before exercise, MI-induced cardiac changes were demonstrated by comparing results to a Sham group; alterations were more intense in rats with large than moderate MI size. Systolic function, evaluated by echocardiogram using the variation in LV fractional area change between after and before exercise, was improved in exercise than sedentary groups. Calsequestrin expression increased in exercised compared to sedentary groups. L-type calcium channel was higher in Mod MI-Ex than Mod MI-Sed. SERCA2a, phospholamban, and Na(+)/Ca(2+) exchanger expression did not differ between groups. CONCLUSION Late exercise improves systolic function and modulates intracellular calcium signaling proteins in rats with moderate and large MI.
Collapse
Affiliation(s)
- Daniele M Guizoni
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | | | - Sefora L R Noor
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Luana U Pagan
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Paula F Martinez
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil; School of Physical Therapy, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - Aline R R Lima
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Mariana J Gomes
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Ricardo L Damatto
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Marcelo D M Cezar
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Camila Bonomo
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Leonardo A M Zornoff
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Katashi Okoshi
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil
| | - Marina P Okoshi
- Internal Medicine Department, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| |
Collapse
|
5
|
Guimaraes JFC, Muzio BP, Rosa CM, Nascimento AF, Sugizaki MM, Fernandes AAH, Cicogna AC, Padovani CR, Okoshi MP, Okoshi K. Rutin administration attenuates myocardial dysfunction in diabetic rats. Cardiovasc Diabetol 2015; 14:90. [PMID: 26185015 PMCID: PMC4504040 DOI: 10.1186/s12933-015-0255-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/03/2015] [Indexed: 01/08/2023] Open
Abstract
Background Oxidative stress plays a major role in diabetic cardiomyopathy pathogenesis. Anti-oxidant therapy has been investigated in preventing or treating several diabetic complications. However, anti-oxidant action on diabetic-induced cardiac remodeling is not completely clear. This study evaluated the effects of rutin, a flavonoid, on cardiac and myocardial function in diabetic rats. Methods Wistar rats were assigned into control (C, n = 14); control-rutin (C-R, n = 14); diabetes mellitus (DM, n = 16); and DM-rutin (DM-R, n = 16) groups. Seven days after inducing diabetes (streptozotocin, 60 mg/kg, i.p.), rutin was injected intraperitoneally once a week (50 mg/kg) for 7 weeks. Echocardiogram was performed and myocardial function assessed in left ventricular (LV) papillary muscles. Serum insulin concentration was measured by ELISA. Statistics: One-way ANOVA and Tukey’s post hoc test. Results Glycemia was higher in DM than DM-R and C and in DM-R than C-R. Insulin concentration was lower in diabetic groups than controls (C 2.45 ± 0.67; C-R 2.09 ± 0.52; DM 0.59 ± 0.18; DM-R 0.82 ± 0.21 ng/mL). Echocardiogram showed no differences between C-R and C. DM had increased LV systolic diameter compared to C, and increased left atrium diameter/body weight (BW) ratio and LV mass/BW ratio compared to C and DM-R. Septal wall thickness, LV diastolic diameter/BW ratio, and relative wall thickness were lower in DM-R than DM. Fractional shortening and posterior wall shortening velocity were lower in DM than C and DM-R. In papillary muscle preparation, DM and DM-R presented higher time to peak tension and time from peak tension to 50% relaxation than controls; time to peak tension was lower in DM-R than DM. Under 0.625 and 1.25 mM extracellular calcium concentrations, DM had higher developed tension than C. Conclusion Rutin attenuates cardiac remodeling and left ventricular and myocardial dysfunction caused by streptozotocin-induced diabetes mellitus.
Collapse
Affiliation(s)
- Julliano F C Guimaraes
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Bruno P Muzio
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Camila M Rosa
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Andre F Nascimento
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Mario M Sugizaki
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Ana A H Fernandes
- Department of Chemistry and Biochemistry, Institute of Biosciences, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Antonio C Cicogna
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Carlos R Padovani
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Marina P Okoshi
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil.
| | - Katashi Okoshi
- Department of Internal Medicine, Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, Brazil. .,Departamento de Clinica Medica, Faculdade de Medicina de Botucatu, UNESP Rubiao Junior, S/N 18618-970, Botucatu, SP, Brazil.
| |
Collapse
|
6
|
Gimenes C, Gimenes R, Rosa CM, Xavier NP, Campos DHS, Fernandes AAH, Cezar MDM, Guirado GN, Cicogna AC, Takamoto AHR, Okoshi MP, Okoshi K. Low Intensity Physical Exercise Attenuates Cardiac Remodeling and Myocardial Oxidative Stress and Dysfunction in Diabetic Rats. J Diabetes Res 2015; 2015:457848. [PMID: 26509175 PMCID: PMC4609864 DOI: 10.1155/2015/457848] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/04/2015] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED We evaluated the effects of a low intensity aerobic exercise protocol on cardiac remodeling and myocardial function in diabetic rats. Wistar rats were assigned into four groups: sedentary control (C-Sed), exercised control (C-Ex), sedentary diabetes (DM-Sed), and exercised diabetes (DM-Ex). Diabetes was induced by intraperitoneal injection of streptozotocin. Rats exercised for 9 weeks in treadmill at 11 m/min, 18 min/day. Myocardial function was evaluated in left ventricular (LV) papillary muscles and oxidative stress in LV tissue. Statistical analysis was given by ANOVA or Kruskal-Wallis. Echocardiogram showed diabetic groups with higher LV diastolic diameter-to-body weight ratio and lower posterior wall shortening velocity than controls. Left atrium diameter was lower in DM-Ex than DM-Sed (C-Sed: 5.73 ± 0.49; C-Ex: 5.67 ± 0.53; DM-Sed: 6.41 ± 0.54; DM-Ex: 5.81 ± 0.50 mm; P < 0.05 DM-Sed vs C-Sed and DM-Ex). Papillary muscle function was depressed in DM-Sed compared to C-Sed. Exercise attenuated this change in DM-Ex. Lipid hydroperoxide concentration was higher in DM-Sed than C-Sed and DM-Ex. Catalase and superoxide dismutase activities were lower in diabetics than controls and higher in DM-Ex than DM-Sed. Glutathione peroxidase activity was lower in DM-Sed than C-Sed and DM-Ex. CONCLUSION Low intensity exercise attenuates left atrium dilation and myocardial oxidative stress and dysfunction in type 1 diabetic rats.
Collapse
Affiliation(s)
- C. Gimenes
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
- Sagrado Coração University, Bauru, SP, Brazil
| | - R. Gimenes
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - C. M. Rosa
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - N. P. Xavier
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - D. H. S. Campos
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - A. A. H. Fernandes
- Department of Chemistry and Biochemistry, Institute of Biosciences, São Paulo State University (UNESP), Brazil
| | - M. D. M. Cezar
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - G. N. Guirado
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - A. C. Cicogna
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - A. H. R. Takamoto
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - M. P. Okoshi
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
| | - K. Okoshi
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), S/N, Rubião Junior District, 18618 970 Botucatu, SP, Brazil
- *K. Okoshi:
| |
Collapse
|
7
|
Penitente AR, Novaes RD, Chianca DA, da Silva MF, Silva ME, Souza AMA, Guatimosim S, Almeida PWM, Alves MNM, Felix LB, Neves CA, Natali AJ. Protein restriction after weaning modifies the calcium kinetics and induces cardiomyocyte contractile dysfunction in rats. Cells Tissues Organs 2013; 198:311-7. [PMID: 24247000 DOI: 10.1159/000355943] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2013] [Indexed: 11/19/2022] Open
Abstract
Protein restriction (PR) is associated with cardiovascular diseases. The purpose of this study was to investigate the effects on single ventricular cardiomyocyte contractile function of a short-term PR after weaning. Male Fischer rats that were 28 days old were randomly divided into a control group (CG, n = 16) and a protein-restricted group (PRG, n = 16). After weaning, CG and PRG animals received isocaloric diets containing 15 and 6% protein, respectively, for 35 days. Biometric parameters were then measured, and the hearts were removed for the analysis of contractile function and calcium transient in isolated cardiomyocytes of the left ventricule (LV), and the quantification of calcium and collagen fibers in LV myocardium. PRG animals had lower body weight (BW) and LV weight (LVW), an increased LVW to BW ratio and a higher proportion of collagen fibers than CG animals. PRG animals exhibited reduced tissue levels of calcium, reduced the length, width and volume of cardiomyocytes and their sarcomere length compared to CG animals. Cardiomyocytes from PRG animals had a lower amplitude of shortening, a slower time to the peak of shortening and a longer time to half-relaxation than those from the CG. Cardiomyocytes from PRG animals also presented a lower peak of calcium transient and a longer calcium transient decay time than CG animals. Taken together, the results indicate that short-term PR after weaning induces a marked structural remodeling of the myocardium parenchyma and stroma that coexists with contractile dysfunctions in single LV cardiomyocytes of rats, which is probably associated with pathological changes of the intracellular calcium kinetics, rather than inadequate available amounts of this mineral in cardiac tissue.
Collapse
Affiliation(s)
- Arlete R Penitente
- Department of General Biology, Federal University of Viçosa, Viçosa, Brazil
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Leopoldo AS, Lima-Leopoldo AP, Sugizaki MM, do Nascimento AF, de Campos DHS, Luvizotto RDAM, Castardeli E, Alves CAB, Brum PC, Cicogna AC. Involvement of L-type calcium channel and SERCA2a in myocardial dysfunction induced by obesity. J Cell Physiol 2011; 226:2934-42. [PMID: 21302294 DOI: 10.1002/jcp.22643] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Obesity has been shown to impair myocardial performance. Nevertheless, the mechanisms underlying the participation of calcium (Ca(2+) ) handling on cardiac dysfunction in obesity models remain unknown. L-type Ca(2+) channels and sarcoplasmic reticulum (SR) Ca(2+) -ATPase (SERCA2a), may contribute to the cardiac dysfunction induced by obesity. The purpose of this study was to investigate whether myocardial dysfunction in obese rats is related to decreased activity and/or expression of L-type Ca(2+) channels and SERCA2a. Male 30-day-old Wistar rats were fed standard (C) and alternately four palatable high-fat diets (Ob) for 15 weeks. Obesity was determined by adiposity index and comorbidities were evaluated. Myocardial function was evaluated in isolated left ventricle papillary muscles under basal conditions and after inotropic and lusitropic maneuvers. L-type Ca(2+) channels and SERCA2a activity were determined using specific blockers, while changes in the amount of channels were evaluated by Western blot analysis. Phospholamban (PLB) protein expression and the SERCA2a/PLB ratio were also determined. Compared with C rats, the Ob rats had increased body fat, adiposity index and several comorbidities. The Ob muscles developed similar baseline data, but myocardial responsiveness to post-rest contraction stimulus and increased extracellular Ca(2+) was compromised. The diltiazem promoted higher inhibition on developed tension in obese rats. In addition, there were no changes in the L-type Ca(2+) channel protein content and SERCA2a behavior (activity and expression). In conclusion, the myocardial dysfunction caused by obesity is related to L-type Ca(2+) channel activity impairment without significant changes in SERCA2a expression and function as well as L-type Ca(2+) protein levels.
Collapse
Affiliation(s)
- André Soares Leopoldo
- Department of Clinical and Cardiology, School of Medicine, UNESP- State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Pinotti MF, Leopoldo AS, Silva MDP, Sugizaki MM, do Nascimento AF, Lima-Leopoldo AP, Aragon FF, Padovani CR, Cicogna AC. A comparative study of myocardial function and morphology during fasting/refeeding and food restriction in rats. Cardiovasc Pathol 2009; 19:e175-82. [PMID: 19914094 DOI: 10.1016/j.carpath.2009.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 08/10/2009] [Accepted: 08/14/2009] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND This study compared the influence of fasting/refeeding cycles and food restriction on rat myocardial performance and morphology. METHODS Sixty-day-old male Wistar rats were submitted to food ad libitum (C), 50% food restriction (R50), and fasting/refeeding cycles (RF) for 12 weeks. Myocardial function was evaluated under baseline conditions and after progressive increase in calcium and isoproterenol. Myocardium ultrastructure was examined in the papillary muscle. RESULTS Fasting/refeeding cycles maintained rat body weight and left ventricle weight between control and food-restricted rats. Under baseline conditions, the time to peak tension (TPT) was more prolonged in R50 than in RF and C rats. Furthermore, the maximum tension decline rate (-dT/dt) increased less in R50 than in RF with calcium elevation. While the R50 group showed focal changes in many muscle fibers, such as the disorganization or loss of myofilaments, polymorphic mitochondria with disrupted cristae, and irregular appearance or infolding of the plasma membrane, the RF rats displayed few alterations such as loss or disorganization of myofibrils. CONCLUSION Food restriction promotes myocardial dysfunction, not observed in RF rats, and higher morphological damage than with fasting/refeeding. The increase in TPT may be attributed possibly to the disorganization and loss of myofibrils; however, the mechanisms responsible for the alteration in -dT/dt in R50 needs to be further clarified.
Collapse
Affiliation(s)
- Matheus Fécchio Pinotti
- Department of Internal Medicine, School of Medicine, State University "Júlio de Mesquita Filho", UNESP, Botucatu, São Paulo, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Sugizaki MM, Leopoldo AS, Okoshi MP, Bruno A, Conde SJ, Lima-Leopoldo AP, Padovani CR, Carvalho RF, Nascimento AFD, Campos DHSD, Nogueira CR, Cicogna AC. Severe food restriction induces myocardial dysfunction related to SERCA2 activity. Can J Physiol Pharmacol 2009; 87:666-73. [DOI: 10.1139/y09-060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have shown that food restriction promotes myocardial dysfunction in rats. However, the molecular mechanisms that are responsible are unclear. We investigated the role of sarcoplasmic reticulum Ca2+-ATPase (SERCA2) on myocardial performance in food-restricted rats. Male Wistar–Kyoto rats, 60 days old, were fed a control or restricted diet (daily energy intake reduced to 50% of the control) for 90 days. Expression of Serca2a, phospholamban (PLB), Na+/Ca2+ exchanger (NCX), and thyroid hormone receptor (TRα1, TRβ1) mRNA was determined by quantitative PCR. SERCA2 activity was measured by using 20 µmol/L cyclopiazonic acid (CPA) in a left ventricular papillary muscle preparation during isometric contraction in basal conditions and during post-rest contraction. Serum concentrations of thyroxine (T4) and thyrotropin (TSH) were also determined. The 50%-restricted diet reduced body and ventricular weight and serum T4 and TSH levels. The interaction of CPA and food restriction reduced peak developed tension and maximum rate of tension decline (–dT/dt), but increased the resting tension intensity response during post-rest contraction. PLB and NCX mRNA were upregulated and TRα1 mRNA was downregulated by food restriction. These results suggest that food restriction promotes myocardial dysfunction related to impairment of sarcoplasmic reticulum Ca2+ uptake as a result of a hypothyroid state.
Collapse
Affiliation(s)
- Mário Mateus Sugizaki
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - André Soares Leopoldo
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Marina Politi Okoshi
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Alessandro Bruno
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Sandro José Conde
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Ana Paula Lima-Leopoldo
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Carlos Roberto Padovani
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Robson Francisco Carvalho
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - André Ferreira do Nascimento
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Dijon Henrique Salomé de Campos
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Célia Regina Nogueira
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Antonio Carlos Cicogna
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| |
Collapse
|
11
|
De Tomasi LC, Bruno A, Sugizaki MM, Lima-Leopoldo AP, Nascimento AF, Júnior SADO, Pinotti MF, Padovani CR, Leopoldo AS, Cicogna AC. Food restriction promotes downregulation of myocardial L-type Ca2+ channels. Can J Physiol Pharmacol 2009; 87:426-31. [DOI: 10.1139/y09-025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Food restriction (FR) has been shown to impair myocardial performance. However, the mechanisms behind these changes in myocardial function due to FR remain unknown. Since myocardial L-type Ca2+ channels may contribute to the cardiac dysfunction, we examined the influence of FR on L-type Ca2+ channels. Male 60-day-old Wistar rats were fed a control or a restricted diet (daily intake reduced to 50% of the amount of food consumed by the control group) for 90 days. Myocardial performance was evaluated in isolated left ventricular papillary muscles. The function of myocardial L-type Ca2+ channels was determined by using a pharmacological Ca2+ channel blocker, and changes in the number of channels were evaluated by mRNA and protein expression. FR decreased final body weights, as well as weights of the left and right ventricles. The Ca2+ channel blocker diltiazem promoted a higher blockade on developed tension in FR groups than in controls. The protein content of L-type Ca2+ channels was significantly diminished in FR rats, whereas the mRNA expression was similar between groups. These results suggest that the myocardial dysfunction observed in previous studies with FR animals could be caused by downregulation of L-type Ca2+ channels.
Collapse
Affiliation(s)
- Loreta Casquel De Tomasi
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - Alessandro Bruno
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - Mário Mateus Sugizaki
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - Ana Paula Lima-Leopoldo
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - André Ferreira Nascimento
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - Silvio Assis de Oliveira Júnior
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - Matheus Fécchio Pinotti
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - Carlos Roberto Padovani
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - André Soares Leopoldo
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| | - Antonio Carlos Cicogna
- Department of Clinical Cardiology, School of Medicine, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP – State University Júlio Mesquita Filho, Rubião Júnior, S/N, Cep. 18.618-000 Botucatu, São Paulo, Brazil
| |
Collapse
|
12
|
Gut AL, Sugizaki MM, Okoshi MP, Carvalho RF, Pai-Silva MD, Aragon FF, Padovani CR, Okoshi K, Cicogna AC. Food restriction impairs myocardial inotropic response to calcium and beta-adrenergic stimulation in spontaneously hypertensive rats. Nutr Res 2009; 28:722-7. [PMID: 19083480 DOI: 10.1016/j.nutres.2008.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 05/27/2008] [Accepted: 06/02/2008] [Indexed: 11/28/2022]
Abstract
Although long-term food restriction (FR) has been shown to induce cardiac remodeling and dysfunction, there are few data on the effects of FR on pressure-overloaded hearts. The aim of this study was to examine the effects of FR on cardiac muscle performance during inotropic stimulation in the myocardium of spontaneously hypertensive rats (SHRs). Male 60-day-old SHRs were subjected to FR for 90 days. Food-restricted animals received 50% of the ad libitum amount of food consumed by the control group. Myocardial function was studied in isolated left ventricular papillary muscle under isometric contraction in basal condition (1.25 mmol/L extracellular Ca(2+) concentration) and after 3 inotropic maneuvers: (1) at postrest contraction of 30 seconds, (2) at extracellular Ca(2+) concentration of 5.2 mmol/L, and (3) after beta-adrenergic stimulation with 10(-6) mol/L isoproterenol. At basal condition, time from peak tension to 50% relaxation was greater in the food-restricted group (P < .05). Inotropic stimulation with postrest contraction and isoproterenol promoted a significant lower increase of developed tension, maximum rate of tension development, and maximum rate of tension decline in the food-restricted compared to the control group. The elevation of extracellular Ca(2+) concentration induced a lower increase of developed tension, maximum rate of tension development, and time from peak tension to 50% relaxation in the food-restricted than in the control group. In conclusion, long-term FR promotes impairment of myocardial inotropic response to calcium and beta-adrenergic stimulation in SHRs.
Collapse
Affiliation(s)
- Ana Lucia Gut
- Department of Internal Medicine, School of Medicine, State University Júlio Mesquita Filho (UNESP), Botucatu, São Paulo, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Sugizaki MM, Dal Pai-Silva M, Carvalho RF, Padovani CR, Bruno A, Nascimento AF, Aragon FF, Novelli ELB, Cicogna AC. Exercise training increases myocardial inotropic response in food restricted rats. Int J Cardiol 2006; 112:191-201. [PMID: 16356569 DOI: 10.1016/j.ijcard.2005.08.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 08/24/2005] [Accepted: 08/29/2005] [Indexed: 11/20/2022]
Abstract
This study evaluated the effects of exercise training on myocardial function and ultrastructure of rats submitted to different levels of food restriction (FR). Male Wistar-Kyoto rats, 60 days old, were submitted to free access to food, light FR (20%), severe FR (50%) and/or to swimming training (one hour per day with 5% of load, five days per week for 90 days). Myocardial function was evaluated by left ventricular papillary muscle under basal condition (calcium 1.25 mM), and after extracellular calcium elevation to 5.2 mM and isoproterenol (1 microM) addition. The ultrastructure of the myocardium was examined in the papillary muscle. The training effectiveness was verified by improvement of myocardial metabolic enzyme activities. Both 20% and 50% food restriction protocols presented minor body and ventricular weights gain. The 20%-FR, in sedentary or trained rats, did not alter myocardial function or ultrastructure. The 50%-FR, in sedentary rats, caused myocardial dysfunction under basal condition, decreased response to inotropic stimulation, and promoted myocardial ultrastructural damage. The 50%-FR, in exercised rats, increased myocardial dysfunction under basal condition but increased response to inotropic stimulation although there was myocardial ultrastructural damage. In conclusion, the exercise training in severe restriction caused marked myocardial dysfunction at basal condition but increased myocardial response to inotropic stimulation.
Collapse
Affiliation(s)
- Mario Mateus Sugizaki
- Department of Internal Medicine, School of Medicine, State University Júlio, Mesquita Filho, UNESP, Botucatu, São Paulo, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Sugizaki MM, Carvalho RF, Aragon FF, Padovani CR, Okoshi K, Okoshi MP, Zanati SG, Pai-Silva MD, Novelli ELB, Cicogna AC. Myocardial dysfunction induced by food restriction is related to morphological damage in normotensive middle-aged rats. J Biomed Sci 2005; 12:641-9. [PMID: 16132105 DOI: 10.1007/s11373-005-7652-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Accepted: 04/18/2005] [Indexed: 10/25/2022] Open
Abstract
Previous works from our laboratory have revealed that food restriction (FR) promotes discrete myocardial dysfunction in young rats. We examined the effects of FR on cardiac function, in vivo and in vitro, and ultrastructural changes in the heart of middle-aged rats. Twelve-month-old Wistar-Kyoto rats were fed a control (C) or restricted diet (daily intake reduced to 50% of the control group) for 90 days. Cardiac performance was studied by echocardiogram and in isolated left ventricular (LV) papillary muscle by isometric contraction in basal condition, after calcium chloride (5.2 mM) and beta-adrenergic stimulation with isoproterenol (10(-6) M). FR did not change left ventricular function, but increased time to peak tension, and decreased maximum rate of papillary muscle tension development. Inotropic maneuvers promoted similar effects in both groups. Ultrastructural alterations were seen in most FR rat muscle fibers and included, absence and/or disorganization of myofilaments and Z line, hyper-contracted myofibrils, polymorphic and swollen mitochondria with disorganized cristae, and a great quantity of collagen fibrils. In conclusion, cardiac muscle sensitivity to isoproterenol and elevation of extracellular calcium concentration is preserved in middle-aged FR rats. The intrinsic muscle performance depression might be related to morphological damage.
Collapse
Affiliation(s)
- Mario Mateus Sugizaki
- Department of Internal Medicine- School of Medicine, Faculdade de Medicina de Botucatu, UNESP, Rubião Júnior, S/N, 18618-000, Botucatu, SP, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|