Study On Relations Between SBP And Ang??ALD In Salt-sensitive Hypertension Rats

Background:Hypertension is main cause of high incidence rate in many regions in China.Salt is related to occurrence and development of hypertension.In the 1970 s,Luft, etc firstly puts forward the concept of salt sensitivity according to the patients with high blood pressure response to high salt intake. Salt-sensitive hypertension,means blood pressure rising with more salt intake. RAAS and sodium water retention are the key to induce salt-sensitive hypertension.RAAS is a cycle of the endocrine system, and may be a general distribution of local secretion system, RAAS is closely related to water and salt metabolism system, which plays a key role in human blood pressure.OBJECTIVE:To observe dynamic the changes of SBP ?plasma Ang? and ALD in rat model of salt- sensitive hypertensive induced by sensory denervation and to explore the mechanism and maybe served as parameters representing the therapeutic efficacy.METHODS:1.Newborn male SD rats were given capsaicin subcutaneously to establish the model. After the weaning period,the rats were divided into 4 groups and fed with different salt diets for 4 weeks: control plus normal salt diet( CON-NS),control plus high salt diet( CON-HS),capsaicin pretreatment plus normal salt diet( CAP-NS),and capsaicin plus high salt diet( CAP-HS).2.Systolic blood pressure were measured·in 4,8,12,16 w by RBP-1.3.the blood(3 to 5ml)of rats was taken from the retro-orbital plexus under anesthesia,which was put into anticoagulant tube, and low temperature frozen to centrifugal plasma, then put in 4 ? refrigerator.4.The plasma levels of(Ang ?) and(ALD) were measured by chenmical immunoassay(RIA).5.Renal function(scr and BUN) was measured in 4 and 16 weeks each ratRESULTS:1.All baby rats were grouped randomly.The CON-NS group blood pressure have no significant difference at the age of 4.8.12.16w(P>0.05), Thetail-cuff systolic blood pressure was significantly higher in the CAP-HS group(141.1±5.5 mm Hg)than that in the CON-NS group(113.5±3.6mm Hg)( P < 0.01),The values of systolic pressure showed tendency in CAP-HS group, SBP in the model group was(153.2±4.5mm Hg),(163.6±4.1 mm Hg),(177.0±8.2 mm Hg)at the age of 4,8,12,16 w,which was significantly different from the control group(P<0.01);SBP of(CON-HS)group rise in 8 weeks,which was(145.4±6.3 mm Hg) at the age of12 w,The SBP was significantly higher in the CON-HS rats than that in the CON-NS rats at the age of 12w( P < 0. 01), It has no significant difference OF SBP between CAP-NS group and CON-NS group(P>0.05)?2.All baby rats were grouped randomly.The CON-NS group Ang? have no significant difference at the age of 4,8,12,16w(P>0.05)?The was significantly lower in the CAP-HS group(250.4±27.0 ng/L)than that in the CON-NS group(540.9±33.7ng/L)( P < 0. 01),: The values Ang?showed tendency in CAP-HS group, Ang?in the model group was(318.2±25.50 ng/L),(399.0±32.6 ng/L),(477.6±29.48ng/L)(153.2±4.5mm Hg),(163.6±4.1 mm Hg),( 177.0±8.2 mm Hg) at the age of4,8,12,16 w,which was significantly different from the control group(P<0.01); Ang?of CON-HS group rise in 8 week,which was(217.2±37.3 ng/L) at the age of12 w,The Ang? was significantly different between CON-HS and the CON-NS group at the age of 12w( P < 0. 01) It has no significant difference of SBP between CAP-NS group and CON-NS group(P>0.05)?3.ALD Change:All baby rats were grouped randomly.The CON-NS group ALD have no significant difference at the age of 4,8,12,16w(P>0.05)?The ALD was significantly lower in the CAP-HS group(256.3±40.4ng/L)than that in the CON-NS group(641.8±51.4 ng/L)( P < 0. 01),: The values ALD showed tendency in CAP-HS group, ALD in the model group was(342.8±38.2ng/L),(443.7±20.9ng/L),(490.5±25.9 ng/L)at the age of 4,8,12,16 w,which was significantly different from the control group(P<0.01);ALD of(CON-HS)group rise in 8 weeks, The ALD was significantly different between CON-HS and the CON-NS group at the age of 12w( P< 0. 01) It has no significant difference OF SBP between CAP-NS group and CON-NS group(P>0.05)?4.the model group CAP- HS group creatine in 4 and 16 weeks CON- NS haveno statistical difference with control group,(P > 0.05), so did the rest of the group,(P > 0.05)5.the model group CAP- HS group BUN in 4 and 16 weeks CON- NS have no statistical difference with control group,(P > 0.05), so did the rest of the group,(P >0.05)CONCLUSION : The of rat model of salt-sensitive hypertensive induced by sensory denervation cay be established succesfully,early increase of blood pressure mainly associated with the water sodium retention, and, RAAS system disorders may be play an important role then in the rats with salt-sensitive hypertension.