Research On The Molecular Mechanism Of The High Salt Diet On Blood Pressure Based On The Theory Of "Salt Restricts Blood "

Objective: Based on the theory of " Salt Restricts Blood " in Huangdi's Classic and the results of previous experiments,the gene chip high-throughput data screening method is applied to detect the gene expression profile of effects of high salt intake on blood pressure.Differential analysis on the expression profile is performed to find the key genes and pathways,and to explain the mechanism of high salt intake induced hypertension from the perspective of " Salt Restricts Blood " on a molecular level.The aims are to provide scientific support for the prevention of hypertension caused by high salt intake by means of a low-salt diet combined with medicine that promotes blood circulation and removes blood stasis,for selecting specific medicine of promoting blood circulation and preventing blood stasis,and to improve the clinical application of the theory in prevention and treatment of hypertension.Methods: According to the pre-experiments,24 healthy 3-month-old Wistar rats(weighing 180g?220g,half male and female)were grouped and numbered into the normal control group(Normal group)and the high salt group(Model group),respectively.There were 12 animals in each group,half male and half female.The model group was administrated 1 m L/100 g of 12% saline,while the normal group 1 m L/100 g of distilled water.Gavage was performed once a day in the morning for 30 consecutive days.During the experiment,the rats in both groups were normally fed(containing 0.3% salts).The changes in body weight and blood pressure were closely observed.The blood pressure of both groups was measured on the 30 th day after gavage,and the whole blood was collected through abdominal aorta.After plasma separation,red blood cell lysate was added,and the white blood cells were obtained by centrifugation.RNA was extracted,hybridized,and scanned.Subsequently,the differential gene expression profile was analyzed.Functional analysis using the GO and KCGG databases was performed to screen out the key pathways and genes for high salt intake induced hypertension.In order to avoid the influence of gender differences,the results were analyzed by gender-based statistical analysis,that is,the results of male rats in the model group were compared with the results of male rats in the normal group,and the results of the female rats in the model group were compared with the female rats in the normal group,and then analyzed.Results:(1)The effect of high salt intake on blood pressure: Compared with the normal group,the blood pressure of the model group rats continued to increase during the experiment.The systolic blood pressure of the female and male rats in the model group were 131.7±3.1 mm Hg and 130.7±5.6 mm Hg(P<0.01),respectively on day8;136.5±3.6mm Hg and 139.7±5.4mm Hg(P<0.01)on day15;158.8±9.0mm Hg and 160.0±10.1mm Hg(P<0.01)on day22;174.0±14.0mm Hg and 172.0±8.8mm Hg on day30(P<0.01).(2)Changes in gene expression profile of high salt intake on blood pressure:(1)The gene expressions between the model group and the normal group showed differences.Analysis of the gene data of the model group showed that compared with the normal group of the same gender,there were 1688 differential expressions in female rats and 907 in male rats in the model group(P<0.05,|log2(fc)|>1),of which 92 genes were co-expressed in both genders,with 81 genes up-regulated and 4 down-regulated.There were 9 genes with significant changes(P<0.01,|log2(fc)|>1),namely kif17,Olr322,LOC103692343,Ndufa4l2,Pax8,pla2g1 b,pla2g3,Prl3d4 and RGD1566226.(2)KEGG analysis showed that compared with the normal group of the same gender,there are 38 pathways for the co-enrichment of differential genes of both genders in the model group,with 3 metabolic pathways(P<0.05),namely,ether ester metabolism pathways(ko00565: Ether lipid metabolism),arachidonic acid metabolism pathway(ko00590: Arachidonic acid metabolism)and ?-linolenic acid metabolism pathway(ko00592: alpha-Linolenic acid metabolism),where genes pla2g3 and pla2g1 b are co-enriched.Conclusions:(1)high salt intake can cause continuous increasing of blood pressure in rats,and the degree of hypertension is positively correlated with the duration of high salt intake.(2)The gene expression of kif17,Olr322,LOC103692343,Ndufa4l2,Pax8,pla2g1 b,pla2g3,Prl3d4 and RGD1566226 in female and male rats of the model group was significantly different(P < 0.01,| log2(FC)| > 1).(3)Ether lipid metabolism,Arachidonic acid metabolism and alpha-Linolenic acid metabolism may be the key pathways for differential expression of gene function in hypertension caused by high salt intake.(4)pla2g3 and pla2g1 b are the target genes for hypertension due to high salt intake.