INTRODUCTION: Total body induced hypothermia and myocardial cooling are effective methods regarding myocardial protection during heart surgery and ischemia. It is described in previous studies that extreme low temperature exposure causes mitochondrial cristae and myofilament disarrangement in cardiomyocytes, however, no investigation has analyzed the effects of cold stress on nuclear size of cardiomyocytes. OBJECTIVES: To evaluate the effects of acute cold stress exposure on the nuclear size of cardiomyocytes in rats. METHODS: The experimental study procedures were performed on 300-310 g adult male Wistar rats. Rats (n=20) were divided into two groups: 1) Control (CON) and; 2) Induced hypothermic (IH) group. Animals of IH group were exposed during 4 hours once at a controlled temperature of - 8 degrees C. It was performed histological analysis of liver and adrenal gland to examine the stress condition of animals. Cardiomyocytes nucleus size were examined by three independent investigators with the same and standardized criteria and analyzed by Bartko's intra-class correlation coefficient (R>0.75 = positive concordance). Student's t test was applied. The significance level was set at P<0.05. RESULTS: The induced hypothermic group presented higher lipid depletion in adrenal gland cells (P<0.05) and higher glycogen depletion in liver glycogen (P<0.05). The experimental group showed lower cardiomyocytes nuclear volume (108 + 1.7 microm(3); P<0.05), it decreased in 76% compared to the control group (142 + 2.3 microm(3)). Bartko's correlation: CON=0.44; IH=0.96, variation analysis between group's means differences was significant. CONCLUSION: These data suggest that acute cold stress exposure induces cardiomyocytes nucleus size reduction in rats.
INTRODUCTION: Total body induced hypothermia and myocardial cooling are effective methods regarding myocardial protection during heart surgery and ischemia. It is described in previous studies that extreme low temperature exposure causes mitochondrial cristae and myofilament disarrangement in cardiomyocytes, however, no investigation has analyzed the effects of cold stress on nuclear size of cardiomyocytes. OBJECTIVES: To evaluate the effects of acute cold stress exposure on the nuclear size of cardiomyocytes in rats. METHODS: The experimental study procedures were performed on 300-310 g adult male Wistar rats. Rats (n=20) were divided into two groups: 1) Control (CON) and; 2) Induced hypothermic (IH) group. Animals of IH group were exposed during 4 hours once at a controlled temperature of - 8 degrees C. It was performed histological analysis of liver and adrenal gland to examine the stress condition of animals. Cardiomyocytes nucleus size were examined by three independent investigators with the same and standardized criteria and analyzed by Bartko's intra-class correlation coefficient (R>0.75 = positive concordance). Student's t test was applied. The significance level was set at P<0.05. RESULTS: The induced hypothermic group presented higher lipid depletion in adrenal gland cells (P<0.05) and higher glycogen depletion in liver glycogen (P<0.05). The experimental group showed lower cardiomyocytes nuclear volume (108 + 1.7 microm(3); P<0.05), it decreased in 76% compared to the control group (142 + 2.3 microm(3)). Bartko's correlation: CON=0.44; IH=0.96, variation analysis between group's means differences was significant. CONCLUSION: These data suggest that acute cold stress exposure induces cardiomyocytes nucleus size reduction in rats.
Authors: José R Cisternas; Vitor E Valenti; Thales B Alves; Celso Ferreira; Márcio Petenusso; João R Breda; Adilson C Pires; Nadir Tassi; Luiz Carlos de Abreu Journal: Int Arch Med Date: 2010-01-27
Authors: Marcelo Ferreira; Paulo Roberto Santos-Silva; Luiz Carlos de Abreu; Vitor E Valenti; Vanessa Crispim; Caio Imaizumi; Celso Ferreira Filho; Neif Murad; Adriano Meneghini; Andrés R Pérez Riera; Tatiana Dias de Carvalho; Luiz Carlos Marques Vanderlei; Erica E Valenti; José R Cisternas; Oseas F Moura Filho; Celso Ferreira Journal: Sports Med Arthrosc Rehabil Ther Technol Date: 2010-08-03
Authors: Marcelo Ferreira; Celso Ferreira; Luiz Carlos de Abreu; Vitor E Valenti; Neif Murad; Adriano Meneghini; Celso F Filho; Japy Angelini de Oliveira Filho Journal: Int Arch Med Date: 2009-10-23
Authors: Guerino Barbalaco Neto; Claudia Rossetti; Natalia A Souza; Fernando LA Fonseca; Ligia Ajaime Azzalis; Virginia Berlanga Campos Junqueira; Vitor E Valenti; Luiz Carlos de Abreu Journal: Eur J Med Res Date: 2012-04-25 Impact factor: 2.175
Authors: Marcelo Ferreira; Vitor E Valenti; Jose R Cisternas; Celso Ferreira; Adriano Meneghini; Celso Ferreira Filho; João R Breda; João A Correa; Carlos Bandeira de Mello Monteiro; Hugo Macedo Junior; Neif Murad; Luiz Carlos de Abreu Journal: Int Arch Med Date: 2011-01-22