The effect of silymarin on memory and learning disorders induced by TiO2 nanoparticles

Titanium dioxide nanoparticles (NP Tio2) are one of the most highly used particles in the world. They are used for biomedical and cosmetic goals. Several studies have shown that NP Tio2 induce oxidative stress in the hippocampus. Silymarin is a flavenolignan that is gained from seed of milk thistle (Silybum marianum) and due to its inhibition of free radicals, acts as an antioxidant in central nerves system. Aim of this research was to study the effect of silymarin on memory and learning disorders induced by TiO2 nanoparticles.
In this experimental study, rats were divided into four groups: control, vehicle, toxic group (150 mg/kg of TiO2 NPs for three weeks orally) as well as silymarin (100 mg/kg for three weeks orally after TiO2 NPs administration). The destructive effect of Nano TiO2 and treatment with silymarin were measured by passive avoidance test using shuttle box.
Oral administration of Tio2 NPs resulted in a significant increase of time of spending in dark box and reduction of time to enter the dark box and silymarin significantly decreased time of spending in dark box (P > 0.001) and treatment with silymarin returned the index to the level of control (P > 0.001).
The results from the present study indicated that silymarin probably due to its antioxidant effects causes improvement of memory and learning disorders induced by TiO2 nanoparticles.