Objective: The aim of the present study was to compare the effects of Portulaca oleracea (Po) seeds extract and those of valsartan on cardiac function in levothyroxine (T4)-treated rats.
Materials and methods: Forty Wistar rats were divided into four groups (n=10): control, levothyroxine (T4), T4 plus valsartan (T4-Val) and T4 plus hydro-alcoholic extract of the P. oleracea seeds (T4-Po). Control group received normal saline. Levothyroxine (100µg/kg/day, i.p.) was administered to three other groups for 4 weeks. Valsartan (8 mg/kg/day, orally) and Po seeds extract (400 mg/kg/day, orally) were administered during the last two weeks of treatment period. At the end of the experiment, echocardiographic and hemodynamic parameters were measured and serum free T4, T3, and T4 were measured.
Results: Administration of T4 for 4 weeks significantly increased serum free T4 levels in T4 group but elevations of free T4 levels in T4-Val group were not significant. Free T4 level decreased in T4-Po (p<0.01) compared to T4 group. Heart rate (HR), heart weight (HW), and left ventricular systolic pressure (LVSP) were significantly increased in T4 group compared to control group while these parameters in the other groups were not significantly different from those of control group. The reduction in HR, HW, and LVSP were more prominent in T4-Po group. Ejection fraction (EF) and fraction shortening (FS) were insignificantly decreased in T4 group compared to control group.
Conclusion: These results showed that treatment of hyperthyroid rats with P. oleracea seeds extract was more effective than valsartan in reducing cardiac changes induced by levothyroxine.
Keywords: Echocardiography; Hemodynamic parameters; Hyperthyroidism; Levothyroxine; Portulaca oleracea; Valsartan.