Effects Of Sleep Deprivation On Heart And Its Mechanism In Rats

Background Sleep deprivation(SD) is a common phenomenon in emergency, especially during wartime or conflict,natural disasters,accidents rescue,and disease crisis such as SARS,it can cause exhaustion in members of armed forces and non-combat casualty.In conditions of high-tech war,sleep deprivation is becoming more serious and mandatory than ever before.Objective The purpose of the study is to observe emotions and action changes, ECG variations and mycardial injury in rats after SD,to monitor the level of stress and myocardial inflammatory reaction caused by sleep deprivation,and to research the mechanism of arrhythmia which provked SD.So as to provide basis for prevention strategies or medications to defend the myocardial injury in the further exploration.Method Male Sprague-Dawley rats were used as research objects,rat models of SD were established by modified multiple platform water environmental method.They were randomly divided into six groups:normal cage control,tank control,SD 1 day,3,5 and 7 days.1.The psychosis,behavior and reaction of rats were observed after SD.2.Standard electrocardiogram of each rat group was recorded under anesthesia.3.The concentration of ACTH,TSH,CORT in serum and GSH,GSH-Px, MDA,SOD in myocardia were monitored in different groups.4.The levels of CRP,ICAM-1,VCAM-1,IL-1βand IL-6 in myocardia were detected by immunohistochemical method after SD.5.The levels of voltage-gated potassium channels(Kv1.5,Kv2.1,Kv4.3) were analysed quantitatively after SD,with Real-time PCR and Western-Blot.Results1.After SD,rats became feverish at first,and then acted as if they were infuriated.At last,they became weaker and weaker,and almost could not alive.2.Main changes in ECG after SD were various tachy- or brady-arrhythmia.3.Levels of ACTH,TSH and CORT showed fluctuations along with the change of SD period.The concentrations of ACTH,TSH and CORT increased at first,and then got to the peak at the 3rd day,the 5th day,the 5th day,respectively.After that they were decreased.4.Oxidative stress indicators in myocardium were changed with the progress of SD,and manifested the increased concentrations of MDA,and the decreased levels of GSH,GSH-Px and SOD activity.5.Inflammatory response factors(CRP,ICAM-1,VCAM-1,IL-6,IL-1β) had little expression in rats myocardial on normal condition,but got rising trend of expression with the prolongation of sleep deprivation.6.With the increase of SD time,arrhythmia-related voltage-gated potassium channels Kv1.5,Kv2.1,Kv4.3 were all upwarded in both Real-time PCR and Western-Blot results.Conclusion1.SD could cause serious arrhythmia,which were worsened with the SD prolongation.2.SD could cause stress-induced myocardial injury.The longer of SD period, the weaker of the antioxidant capacity.3.SD could cause myocardial inflammatory injury,which became serious with the SD period.4.The reduced levels of myocardial voltage-gated potassium channel Kv1.5, Kv2.1,Kv4.3 may be one of the mechanisms of SD caused arrhythmia.