An experimental model on the protective impact of nanosilymarin on ulcerative colitis induced by TNBS in rats: The inclusion of TLR4 / NF-κB pathway

The present work aimed to assess the protective impacts of nanosilymarin or silymarin on colitis induced by TNBS in rats.

Induction of acute colitis was conducted by rectally administering 2 ml of TNBS solution. About 2 hr followed by induction of colitis, the rates were given dexamethasone (2 mg / kg), normal saline, silymarin (50, 100, and 200 mg / kg), and nanosilymarin (50,100, and 200 mg / kg) orally for two weeks. Damage was assessed at the macroscopic and microscopic levels. MPO enzyme activity was measured using biochemical technique and also ELISA kit was used to measure tissue levels of TNF-α and IL-1β and Western blot analysis was utilized to study the expression level of P65 TLR4 and pNF-κB proteins.

According to the results, dexamethasone (2 mg / kg) and nanosilimarin (200 mg / kg) reduced tissue damages than the TNBS group (P<0.001). Moreover, these drugs reduced MPO activity (P<0.001) and levels of TNF-α and IL-1β (P<0.001) in colon tissue than the TNBS group and also the expression of p65 TLR4 and pNF-κB proteins was decreased when in comparison to the TNBS group.

It is proposed that nanosilimarin reduce colon inflammation in TNBS-induced experimental colitis by inhibition of the TLR4 / NFκB molecular pathway.