Effect Of Drinking Cold Water On Organ Damage In High-salt Diet–fed Rats And Hydrogen-rich Water Intervention

BackgroundHypertension is the primary risk factor for cardiovascular and cerebrovascular disease,and can be associated with heart,aorta and kidney and other organ damage.High salt diet can not only induce hypertension,but also be a risk factor for organ damage independent of blood pressure.Cold stimulation or hypothermia may lead to elevated blood pressure,which is involved in oxidative stress and activation of the renin angiotensin system and so on.Therefore,in this study,we test the hypothesis that cold water as a cold stimulus,may be by increasing blood pressure and oxidative stress and other mechanisms to promote organ damage in high-salt diet-fed rats;hydrogen as an antioxidant,may has a protective effect on this organ damage.ObjectiveTo investigate the effect and mechanism of drinking cold water for long term on organ damage in rats fed with high salt diet,and the intervention effect of hydrogen.MethodsMale Wistar rats were randomly divided into 6 groups: 1.The control group,fed 0.5%NaCl diet and tap water at room temperature;2.Cold water group,fed 0.5%NaCl diet and 4?cold water.3.Cold hydrogen-rich water group,fed 0.5%NaCl diet and 4?cold hydrogen-rich;4.High salt group fed 8%NaCl and tap water at room temperature;5.High salt plus cold water group,fed 8%NaCl diet and 4?water;6.High salt plus cold hydrogen-rich water group,fed 8%NaCl and 4? hydrogen-rich water.Non-invasive blood pressures were measured by tail cuff occlusion.After 8 weeks of feeding,5 rats were randomly selected from each group.Systolic blood pressure(SBP),diastolic blood pressure(DBP),mean arterial pressure(MBP),heart rate(HR),systolic blood pressure variability(SBPV),diastolic blood pressure variability(DBPV),mean pressure variability(MBPV)and baroreceptor sensitivity(BRS)were monitored in conscious,freely-moving rats.And then morphometry and histopathology of heart,thoracic aorta and renal were performed.Plasma malondialdehyde(MDA),nitric oxide(NO)content,interleukin-6(IL-6)level,superoxide dismutase(SOD)activity,norepinephrine(NE),renin(Ren),angiotensin ?(Ang?)and Aldsterone(Ald)level were measured.Results:1.Morphological changes of rats.Compared with the control group,the weight of the aorta in the high salt diet group was increased at 2 weeks;While compared with the high salt fed group,left ventricular thickness increased significantly in high salt and cold water group;Compared with the high salt and cold water group,the left ventricular thickness in the high salt plus cold hydrogen-rich water group decreased,which indicated that the hydrogen had an effect on it.Compared with the control group,there was an increase in left ventricular weight in cold water group.After 8 weeks of feeding,compared with the control group,left ventricular weight,left ventricular weight,left ventricular weight index,left ventricular thickness,aortic weight,right kidney weight index in high salt fed rats group were significantly increased,indicating that long-term high salt diet could lead to heart,aorta and kidney abnormalities.Compared with the high salt fed group,high salt feeding plus cold water rats reduced body weight,left ventricular weight index,left ventricular thickness,right kidney weight index increased;Compared with the high salt feeding plus cold water group,left ventricular mass index,left ventricular thickness,right kidney weight index in high salt plus hydrogen-rich group decreased,indicating that target organ damage caused by high salt and cold water could be protected by the hydrogen.Compared with the control group,left ventricular mass index,left ventricular thickness,aortic weight,right kidney weight index in the control group cold rat were significantly increased,indicating that long-term drinking cold water can also lead to heart,aorta and kidney abnormalities.Compared with the cold water group,left ventricular mass index,left ventricular thickness,aortic weight and right kidney weight index in cold hydrogen-rich water group were decreased,indicating that hydrogen had protective effects on.heart,aorta and kidney abnormalities in cold water group.2.Histopathology changes.After 8 weeks of feeding,myocardial hypertrophy and myocardial fiber necrosis fracture,aortic hypertrophy,appear mucoid degeneration,kidney glomerulus,renal tubular epithelial cells with vacuolar degeneration,interstitial inflammatory cell infiltration and thickening of the arteries were observed in high salt,and high salt plus cold water group.Whereas these changes were less in high salt plus hydrogen-rich water group,3.Hemodynamic changes.Change the fixed period of 8 consecutive weeks of tail cuff blood pressure of rats in each group.Compared with the control group,high salt fed group SBP and DBP continued to eighth weeks of the end of the experiment has increased from second weeks to eighth weeks.MBP always increased from third weeks.Compared with the high salt fed group,high salt diet plus cold water group SBP,DBP and MBP increased.Compared with the high salt feeding plus cold water group,high salt feeding plus cold hydrogen water group SBP,DBP and MBP were not significantly changed,suggesting that hydrogen had no effect on blood pressure.Compared with the control group,the control group of SBP rats to cold water continued to eighth weeks has increased since the second week,DBP from second to fifth weeks increased,MBP respectively in second weeks,fourth weeks,seventh weeks was significantly increased;and the control group compared with the control + cold water,cold water hydrogen group SBP,DBP,MBP no significant change.The use of hemodynamics in conscious rats after test showed that: compared with the control group,high salt diet group rats SBP,DBP,MBP,SBPV,DBPV,MBPV was increased,the cold water control group rats SBP,SBPV,DBPV,MBPV and HR were also increased,showed that high salt diet and drinking water are long-term increased systolic blood pressure and blood pressure variability;compared with the high salt fed group,increased high salt feeding + cold water group SBP,DBP,MBP,SBPV,DBPV,MBPV and HR were significant,that can be applied after the cold water stimulation,high salt fed rats significantly increased blood pressure,blood pressure variability and heart rate.Compared with the high salt and cold water group,there was no significant change in SBP,DBP and MBP in the high salt + cold water group,but SBPV,DBPV,MBPV and HR were all changed.The results showed that the effect of hydrogen peroxide on the fluctuation of blood pressure in rats with high salt water ice could be improved.Compared with the control group,there was no significant change of SBP,DBP and MBP in the control + cold hydrogen water group,but SBPV,DBPV,MBPV and HR had significant changes,suggesting that hydrogen could improve the BRS function of rats induced by long-term ice water.4.The change of baroreceptor reflex function.Compared with the control group,BRS of high salt fed group decreased significantly at 8 weeks;compared with the high salt fed group,BRS of high salt and cold water feeding group also significantly reduced;compared with high salt and cold water feeding group,BRS of high salt plus cold hydrogen water group significantly increased.Compared with the control group,BRS of cold water group decreased significantly.BRS between cold water feeding group and cold hydrogen water group has no difference.5.Changes in oxidative stress,inflammation and renin-angiotensin-Aldsterone system and other biochemical indexes.Compared with the control group,Ren,Ang? and Ald decreased in the plasma of the high salt group,and the contents of NE,MDA and IL-6 in the left ventricle,aortic arch,kidney and plasma were increased,and Ren,Ang? and Ald in the left ventricle,aortic arch,kidney were increased and the content of NO and SOD activity decreased;compared with the high salt group,the levels of NE in kidney,Ren,Ang?,Ald,MDA,SOD and IL-6 in plasma,left ventricular,aortic arch and kidney were increased in high salt plus cold water group,and the content of NO and activity of Cr decreased;compared with the high salt feeding plus cold water group,reduce the high salt feeding plus cold water hydrogen group in plasma and tissues of MDA,RA,Ang?,Ald,NE content,NO content increased,SOD activity increased.Conclusion:1.Long term cold water consumption could aggravate the injury of organs in rats fed with high salt diet,and its mechanism is related to the increase of blood pressure,blood pressure fluctuation,oxidative stress and activated renin-angiotensin-Aldsterone system.2.The protective effect of hydrogen on theorgan damage induced by cold water combined with high salt feeding might be related to the antioxidant stress of hydrogen.