Finasteride effectively attenuates the impairments of left ventricular function and cardiac sympathovagal balance in both aging and obese male rats via reducing systemic oxidative stress

Abstract

Abstract Background Cardiovascular diseases are commonly found in the elderly and obese population manifested by left ventricular (LV) dysfunction and impaired cardiac sympathovagal balance. Finasteride (FIN), a 5-alpha reductase inhibitor (5-ARI), is a universal prescription for patients with benign prostatic hyperplasia (BPH). Since BPH is commonly found in obesity and aging, it is essential to investigate whether FIN could have an impact on the LV function and cardiac sympathovagal balance in either elderly or obese conditions. Purpose We tested the hypothesis that impaired LV function and cardiac sympathovagal balance are observed in aging and obese conditions, and FIN improves these parameters through a reduction of systemic oxidative stress in both aging and obese male rats. Methods Twenty-four male Wistar rats (aged 8 weeks old) were randomly divided into 3 groups (n=8/group) to receive one of the followings: 1) normal diet (ND) feeding, 2) ND feeding with D-galactose injection (150 mg/kg/day, subcutaneous injection, 18 weeks) for creating an aging model, and 3) HFD feeding for 18 weeks for creating an obesity model. At week 13, rats in each group were divided into 2 subgroups (n=4/subgroup) and received either a vehicle (drinking water) or FIN (5 mg/kg/day) via oral gavage. At the end of treatment, echocardiography was performed to assess LV function, and the heart rate variability (HRV) was determined to quantify cardiac sympathovagal balance. The blood was collected, and serum was used to determine serum malondialdehyde (MDA) levels as a marker of systemic oxidative stress. Results At week 13, D-galactose injection successfully induced aging as indicated by increasing cardiac p53 protein expression. HFD also caused obesity in those rats as indicated by increased body weight and visceral fat weight. LV dysfunction (as indicated by reduced %LVEF and %LVFS) and cardiac sympathovalgal imbalance (as indicated by an increased LF/HF ratio) were observed in both models (Figure 1A-C). This functional impairment was associated with an increased MDA levels (Figure 1D). Treatment with FIN successfully reduced cardiac sympathovagal imbalance in both models (Figure 1C); however, an improvement of LV function was found only in aging rats-treated with FIN (Figure 1A, B). Consistent with a reduction of cardiac sympathovagal imbalance, FIN decreased systemic oxidative stress in both models (Figure 1D). Conclusions FIN effectively improved cardiac sympathovagal balance in rats under both aging and obese conditions. However, FIN reduced LV dysfunction only in aging rats. Interestingly, FIN did not affect these cardiac parameters in normal healthy rats. These findings suggest the cardioprotective potential of FIN in both aging and obese populations.