The present study was designed to compare the potential of turmeric and its active principle curcumin on T(3)-induced oxidative stress and hyperplasia. Adult male Wistar strain rats were rendered hyperthyroid by T(3) treatment (10 μg · 100 g(-1) · day(-1) intraperitoneal for 15 days in 0.1 mM NaOH) to induce renal hyperplasia. Another two groups were treated similarly with T(3) along with either turmeric or curcumin (30 mg kg(-1) body weight day(-1) orally for 15 days). The results indicate that T(3) induces both hypertrophy and hyperplasia in rat kidney as evidenced by increase in cell number per unit area, increased protein content, tubular dilation and interstitial edema. These changes were accompanied by increased mitochondrial lipid peroxidation and superoxide dismutase activity without any change in catalase activity and glutathione content suggesting an oxidative predominance. Both turmeric and curcumin were able to restore the level of mitochondrial lipid peroxidation and superoxide dismutase activity in the present dose schedule. T(3)-induced histo-pathological changes were restored with turmeric treatment whereas curcumin administration caused hypoplasia. This may be due to lower concentration of curcumin in the whole turmeric. Thus it is hypothesized that regulation of cell cycle in rat kidney by T(3) is via reactive oxygen species and curcumin reveres the changes by scavenging them. Although the response trends are comparable for both turmeric and curcumin, the magnitude of alteration is more in the later. Turmeric in the current dose schedule is a safer bet than curcumin in normalizing the T(3)-induced hyperplasia may be due to the lower concentration of the active principle in the whole spice.
Keywords: Curcumin; Hyperplasia; Kidney; Oxidative stress; Thyroid; Turmeric.