Beneficial effects of turmeric oil and sunflower seed oil in the rapid kindling rat model of epileptogenesis.

PURPOSE: Curcumin, a major Curcuma longa constituent, has shown anticonvulsant effects in preclinical seizure and epileptogenesis models. However, its poor bioavailability and modest, non-persistent effects in the rat rapid kindling model, limits its potential. Therefore, we aimed to investigate whether turmeric oil, a more lipophilic and better bioavailable C. longa fraction, modulates seizure development in the rat rapid kindling model.

METHODS

Rats were electrically stimulated via the angular bundle for 4 days (9 stimulations/day, 45 min apart), 1 h after intraperitoneal (i.p) injection of saline (n = 8), vehicle (sunflower seed oil, n = 8), or turmeric oil (in vehicle; n = 7). Treatment was given for 1 week, followed by a 1-week washout. A kindling re-test was then performed without any injections. Behavioral seizures were scored using Racine's scale. Immunohistochemistry for IBA1 (microgliosis) and vimentin (astrogliosis) performed in the dorsal and ventral hippocampus.

RESULTS

Vehicle and turmeric oil reduced behavioral seizure severity compared with saline. After washout, only turmeric oil exhibited reduced behavioral seizure severity during the initial re-test stimulations. Kindling resulted in reactive microgliosis and astrogliosis in the hippocampus, but the density of IBA1 and vimentin-positive cells did not differ between groups.

CONCLUSIONS

Both vehicle and turmeric oil exerted anti-ictogenic effects in the rapid kindling model, without attenuating kindling-induced gliosis. Notably, turmeric oil showed modest short-term persistence of its anti-ictogenic effects after washout, consistent with either a transient residual pharmacological action or a limited modulation of seizure progression within this paradigm, but not allowing firm conclusions regarding disease-modifying effects. These findings also underscore the importance of careful vehicle selection in preclinical epilepsy research.