Studies On The Expression Of ENOS,iNOS And Heart, Kidney Apoptosis In Salt-sensitive Hypertensive Rats

Objectives: To detect the expression of eNOS,iNOS in mRNA and protein in kidney and heart on salt-sensitive hypertensive rats induced by sensory denervation. To analyse the relationship between the expression of eNOS and salt-sensitive hypertension, and the relationship between the expression of iNOS and heart,kidney apoptosis, to propose the formation of salt-sensitive hypertension and heart,kidney cell damage.Methods: Wistar rats, male, birth weight of 6-7g. The rats were divided into two major groups:Group I: newborn male Wistar rats were given 50 mg/kg capsaicin subcutaneously on the 1st and 2nd day of life. Group II: the control group rats were injected with 10% volume of ethanol and 10% Tween 80 in saline.After the Lactation period (three weeks),two major groups male rats were divided into 2 groups, separately,a total of four groups (n = 7) were fed with normal or high salt feeds:①normal control group, (containing 0.5% NaCl) diet (CON-NS)②control group + high salt diet (containing 4% NaCl) (CON-HS)③capsaicin + normal diet (containing 0.5% NaCl) (CAP-NS)④capsaicin + high salt diet (containing 4% NaCl) (CAP-HS). Both tail-cuff systolic blood pressure and body weight were measured at given times. The rats were killed at the 4 weeks after division, the change of kidney and heart histopathology were observed, spectrophotometry to detect heart and kidney iNOS activity, NO content;immunohistochemistry was performed to detect the expression of eNOS and iNOS protein in kidney and heart, the expression of eNOS and iNOS mRNA in kidney and heart was determined by RT-PCR, the level of apoptosis was assessed by single cell gel electrophoresis.Results: After re-grouping 4 weeks, the tail systolic blood pressure of rats significantly increased and CAP-HS group systolic blood pressure was significantly higher than the other three groups (P<0.05). We observed that the male Wistar rats weight monitoring after different four disposal methods, no significant difference among groups at the end of the experiment(P>0.05).Pathology hematoxylin-eosin staining under light microscope shows: compared with the CON-NS group, CAP-HS group of renal tubular expansion, glomerular significant number of bleeding points, glomerular capillary basement membrane thickening; compared with CON-NS group, CAP-HS group cardiac muscle cell hypertrophy, muscle fiber disarrangement, nuclei arranged in irregular. Spectrophotometry showed the active of iNOS and level of No in CAP-HS significantly higher when compared with CON-NS group. Immunohistochemistry showed that the kidney of rats, eNOS protein expression was mainly distributed in the renal tubular endothelial cells, CAP-HS group of eNOS protein was significantly decreased compared with CON-NS group (P<0.01).In heart , eNOS protein expression CAP-HS group of eNOS protein was significantly decreased compared with CON-NS group (P<0.05). In heart and kidney, CAP-HS group of iNOS protein was significantly increased compared with CON-NS group (P <0.01).RT-PCR results showed that CAP-HS group myocardial tissue iNOS mRNA significantly increased compared with CON-NS group (P<0.01).In kidney, iNOS mRNA significantly increased compared with CON-NS group (P<0.05). In heart,eNOS mRNA significantly decreased compared with CON-NS group (P<0.01). In kidney, eNOS mRNA significantly decreased compared with CON-NS group (P <0.05).Single cell gel electrophoresis results showed that in myocardial tissue, CAP-HS group the number of apoptotic cells significantly increased compared with CON-NS group (P<0.05). In kidney, the number of apoptotic cells significantly increased compared with CON-NS group (P <0.01).Conclusions: The salt-sensitive hypertensive rats induced by sensory denervation was replicated successfully. The blood pressure increased in CAP-HS rats.The decreased express of eNOS mRNA and protein was related with the formation of salt-sensitive hypertension. The increased express of iNOS mRNA and protein could produce a large number of NO in heart and kidney. NO can increase the apoptosis and the damage of in salt-sensitive hypertensive rats of heart and kidney .