Effect of oral administration of methanolic root extract of Saussurea costus to rats after propylthiouracil-induced hypothyroid obesity

Hypothyroid obesity is associated with various metabolic abnormalities. This study aimed to assess the ameliorating property of Saussurea costus methanolic extract (SME) in hypothyroid obese rats via its oral administration for 30 consecutive days. Blood samples were collected for biochemical determinations; the liver and heart were removed for the determination of oxidative stress markers; and the thyroid gland was dissected out for histopathological examination. The total phenolic compounds, radical scavenging activity, and reducing power of the extract were also determined. The results showed that the extract possessed considerable values of phenolic compounds, radical scavenging activity, and reducing power. Also, hypothyroid obesity induced significant increases in serum insulin, glucose, and TSH levels concomitant with significant decreases in the levels of total T3, free T3, free T4, and total T4 hormones. The levels of hepatic and cardiac MDA and NO increased significantly while the values of GSH, GPx, and catalase decreased significantly in hypothyroid obese modeled rats. Moreover, hypothyroid obesity significantly increased serum ASAT, ALAT, CK-MB, and LDH activities but did not affect levels of urea and creatinine. In addition, serum cytokines TNFα, IL-1β, IL- 6, IL-4, and IL-10 levels increased significantly in hypothyroid obese rats compared to control group. Lipid profile markers also disturbed significantly in hypothyroid obese rats. Interestingly, both SME and the reference drugs (L-Thyroxine) succeeded to counteract the alterations in the values of the above parameters and improve the histological picture of thyroid gland but with different levels, where SME was more safe than L-Thyroxine. It could be concluded that the Saussurea costus extract is a promising natural source that could be used more safely than L-Thyroxine to prevent and reduce thyroid dysfunction associated with obesity and its complications, benefiting patients and health institutions.