Objectives This study‘s object was to observe the comparative effects of Yangkyuksanhwa-tang, Palmulgunja-tang and Cheongpyesagan-tang on the chronic LT4(levothyroxine) induced hyperthyroidism in rats.
Methods Six groups, each of 8 rats in group, were used in this study. Saline and distilled water treated rats are intact control group. Hyperthyroidism was induced by daily subcutaneous LT4 300 μg/kg treatment for 27 days(LT4 control). Since 12th LT4 treatment PTU(propylthiouracil) 10 mg/kg was intraperitoneal injected(PTU group) and aqueous extracts of Yangkyuksanhwa-tang, Palmulgunja-tang and Cheongpyesagan-tang(YS, PG and CS) 500 mg/kg were orally administrated(YS, PG, CS group), once a day for 15 days. The differences in the body, thyroid gland and epididymal fat pad weights, serum T3(tri-iodothyronine), T4(thyroxine), TSH(thyroid-stimulating hormone), thyroid gland and epididymal fat pad histopathology, liver weight, AST(asparte aminotransferase), ALT(alanine aminotransferase) concentrations, hepatic lipid peroxidation, GSH(glutathione), SOD(superoxide dismutase), CAT(catalase) activities, liver histopathology were observed to evaluate effects on hyperthyroidism, liver damages and antioxidant effects.
Results As results of LT4 treatment, hyperthyroidism and related liver damages such as lower body, thyroid weights, higher serum T3, T4, AST, ALT levels, thinner follicular lining epithelium in thyroid glands were observed. However, these symptoms were inhibited by oral treatment of YS, PG and CS. As compared with PTU treatment, these herbal prescriptions showed lower overall efficacy on the hyperthyroidism, but YS showed more favorable effects on the hepatic antioxidant defense systems.
Conclusions This results suggest that YS, PG and CS favorably control the LT4 induced hyperthyroidism and related liver damages in rats through modulation of the hepatic antioxidative defense systems.