Effects of Oral Spironolactone on TNF-α Expression of Myocardial Tissues in Spontaneous Hypertension Rats

Objective:To investigate the effect of low-dose oral spironolactone(SPIRO) on the expression of TNF-α of myocardial tissues in spontaneous hypertension rats(SHR).Methods:Twenty 8-week-old male SHR were randomly divided into SPIRO group(SHR-SPIRO,n=10) and control(CON) group(SHR-CON,n=10).Seven sex-age matched Wistar Kyoto rats(WKY group) were used as the third group.The SPIRO was dissolved in distilled water,and animals were intragastrically administrated SPIRO and weighed once weekly to adjust the drug dosage [20 mg/(kg·d)].The evaluation was performed after 16 weeks of treatment.The rats were anesthetized with 1 g/kg urethane intraperitoneally at 24-week-old.The systolic pressure,diastolic pressure and mean arterial blood pressure were detected by a tube that was pierced into the carotid artery and was connected with physiological function experimental system.The hearts of rats were rapidly isolated and were cut into two parts.One was fixed in 10% buffered formalin fixation solution for immunohistochemistry examination,the other one was thrown quickly into liquid nitrogen.The TNF-α level of left ventricular homogenate was detected by enzyme linked immunosorbent assay.Results:There were no significant differences in values of systolic blood pressure,diastolic blood pressure and mean arterial pressure between SHR-SPIRO group and SHR-CON group(P 0.05).But there were significantly higher systolic blood pressure,diastolic blood pressure and mean arterial pressure in the two groups compared to those of WKY group(P 0.05).The concentration of TNF-α in myocardial tissues was significantly higher in SHR-CON group than that of WKY group(P 0.01).The level of TNF-α expression in myocardial tissues decreased significantly in SHR-SPIRO group than that of SHR-CON group(P 0.01).Conclusion:The level of TNF-α expression in myocardial tissues increased in hypertension rats.The low-dose oral spironolactone can decrease the concentration of TNF-α of myocardial tissues in hypertension rats.