AIM: To investigate the action of testosterone on atherosclerosis in a rabbit model. METHODS: 37 male cholesterol-fed rabbits were divided into five groups: castration group: castrated rabbits without exogenous testosterone administration; testosterone Ⅰ group: castrated rabbits with exogenous testosterone 0.25 mg?kg -1?d -1; testosterone Ⅱ group: castrated rabbits with exogenous testosterone 2.5 mg?kg -1?d -1; testosterone Ⅲ group: castrated rabbits with exogenous testosterone 12.5 mg?kg -1?d -1. The sham operation group was also set. Three months later, the levels of testosterone, blood lipids (including TG, HDL-C, LDL-C), PAI activity, nitric oxide (NO) content, endothelin (ET), angiotensin Ⅱ (AngⅡ) in blood were detected. RESULTS: It showed that testosterone in castration group was the lowest. There was no significant difference of TG or LDL-C between castration group and the other four groups. HDL-C in castration group was lower than that in other four groups. NO content of castration group was lower than that in others, but PAI activity, ET and AngⅡ concentration were higher than that in other groups. CONCLUSION: Testosterone is a protective factor against atherosclerosis in male rabbits.

To explore influence of interventional closure on heart rate in patients with atrial septal defect . Methods : A total of 63 patients with atrial septal defect undergoing percutaneous interventional closure in our hospi‐tal were selected. Heart rate was compared before and after surgery ,and correlation among heart rate ,age ,occlude size and preoperative pulmonary artery pressure was analyzed .Results : Compared with before surgery ,there was significant reduction in heart rate [(75.22 ± 8.23) beats／min vs. (64.87 ± 10. 65) beats／min] after percutaneous in‐terventional closure of atrial septal defect , P＝0.001 ;Pearson correlation analysis indicated that postoperative heart rate change was not correlated with age ,occluder size and pulmonary artery systolic pressure (PASP ) ( r＝0.017－0.182 , P＞0.05 all) . Compared with patients without preoperative pulmonary artery hypertension ,there was sig‐nificant rise in postoperative reduction amplitude of heart rate [ (2.28 ± 9.81) beats／min vs. (11. 35 ± 10.73) beats／min] in those with preoperative elevated pulmonary systolic pressure (≥25mmHg) , P＝0.038 .Conclusion : After percutaneous interventional closure ,heart rate significantly decreases in patients with atrial septal defect .Presence of preoperative pulmonary artery hypertension can be regarded as a risk predictor for postoperative heart rate reduction .