Infect Of The Stress On The Function And Structure Of The Heart Of Rat

Infect of the stress on the function and stracture of the heart of ratObjective:To compare the difference between acute stress and chronic stress on the function and structure of the heart of ratMethods:24 Male 2-month-old Wistar rats were randomly divided into three groups: normal control group (N= 8); chronic stress group (N= 8);acute stress group (N= 8) giving random stimulus at different times during the day, while water fasting,checking ECG 48 hours befNCe stress and 48 hours after the trip, References of model making period in literature were made, then the date of termination was chosen.fasting for 12 hours, taking blood from the superiNC vena cava. Measuring creatine kinase with automatic biochemical analysis, detectiving ACTH by the way of enzyme-linked immunosorbent assay and analysing the data meaningby statistical analysis. Rats were sacrificed and dissected to produce the pathological myocardial tissue slices, HE staining, immunohistochemical staining, electron microscopy sample preparation, inorder to observe the histological changes of myocardium.Results:(1) After a week of stress,rats perfomed behavior of excitement and anxiety in NCder to avoid stimulating, contained resistance,screaming,increasing Fenqiu,breathing faster, frightening, staring eyes, a high degree of vigilance, etc. the behaviNC of excitement gradually reduced after two weeks, acted suppression and depression later, Hair was sparse, messy, and dull, showed an air of fatigue,eye lost its luster, body shape was thin, eating reduced, ability to respond significantly reduced, etc.. (2) Body weight changed before and after stress, stress group compared with control group(P<0.01), compared with the pre-test (P <0.01).The control group gained weight more obvious.Stress group compared with the control group, there was no significant difference between the first week and the second week, there was a statistically significant difference between the third week and forth week (P<0.01). (3) Blood pressure stress group compared with the control group during the first 2-4 weeks,there was a statistically significant difference (p<0.01), Stress group rats,, blood pressure increased from the first (115.7±12.3) mmHg to (125.9±8.1) mmHg within 2-4 weeks, there was significant difference compared with the pre-existence of stress,mean arterial blood pressure of control group was no significant difference befNCe and after experiment.. (4) ACTH is key hormone of the hypothalamus-pituitary-adrenal axis, can be used as indicatNC for evaluation of stress state. A group compared with B group,the difference was statistically significant (p<0.01), (p<0.01), The results showed that:The ACTH level of B group was higher than that of the control group, it was in stress state. (5) The difference of myocardial enzyme activity of rats in each group was statistically significant by analysis of variance (P <0.01 NC P<0.05). Further examing the difference between the two groups, the myocardial enzyme activit of stress group was significantly higher than the control group (P<0.05).(6) after 4 weeks, rats divorced from the stress source fNC one day, ECG recorded:①Heart rate changes:all rats of stress group expressed sustained Sinus tachycardia, Atrial premature beat, Ventricular contraction (Figure 1)。②Heart rate increased from (371.3±12) times/min to (468.7±10) times/min (P<0.01), the RR interval shortened from (171.6±5) ms to (111.5±0.5) ms (P<0.01). The above indicators of the control group was not different before and after experiment.③ST-segment elevated up or down, There was low-lying or inverted T-wave, there were no ST-T changes before stress.Conclusion:(1) In this study, the establishment of multi-stress model of chronic stress, animal showed a similar stress state of the main symptoms of human, suggesting that in this experiment, animal models can be used for general stress-disease research. (2) HPA stress-induced activity maintains a high level in short-term, chronic stress may lead to a more multi-lasting arrhythmias. This study laid a foundation for exploring the sustainability of the early molecular mechanisms of arrhythmia research. (3) Creatine kinase (CK) of stress rats was significantly higher,myocardial biopsy found myocardial injury, Such as hypertrophy, apoptosis. Ultrastructure showed that mitochondrial was swelling, rounded, and so on. (4) The preliminary work provided sufficient experimental evidence for further clarifying the psychological stress-induced miRNA mechanism of myocardial injury and function analysis...