Antinociceptive, anti-inflammatory and lesion-reducing effects of thalidomide in a rat model of endometriosis

In this study we tested three oral doses of thalidomide (25, 50, and 100 mg/kg/day) against leuprolide acetate and saline controls in a rat model of endometriosis induced by mesenteric auto transplantation. Outcomes spanned behavioral pain assessment (Rat Grimace Scale, Von Frey, RotaRod), plasma cytokine profile (TNF-α, IFN-γ, IL-6, IL-10), implant volume, and Keenan histological scoring. Two findings stand out: (i) oral thalidomide produced a dose-dependent reduction in spontaneous and evoked pain together with regression of endometriotic implants and (ii) within the 21-day window, the antinociceptive and anti-inflammatory effects of thalidomide preceded the response observed in the leuprolide arm, consistent with the known pharmacodynamic delay of GnRH agonists.