Israel Medical Association Journal

Background: Rectal administration of iodoacetamide induces colitis by blocking sulphhydryl groups and generating inflammatory mediators. Thalidomide, a non-barbiturate hyp­notic, also has an anti-inflammatory effect, presumably by suppressing the production of tumor necrosis factor alpha. In patients with Crohn’s disease, neutralization or suppression of TNFá reduces inflammation.

Objectives: To evaluate the effects of thalidomide in a model of experimental colitis.

Methods: Colitis was induced in rats by intracolonic administration of 3% iodoacetamide. In the treatment group, thalidomide 50 mg/kg was given daily by gavage and continued for 7 days until the rats were sacrificed. Their colons were then processed for wet weight, lesion area, weight of mucosal scraping, myeloperoxidase activity and histology. Serum levels of TNF were determined.

Results: Colonic wet weight, lesion area, myeloperoxidase activity and serum levels of TNFá were significantly lower (P<0.05) in the treatment group (iodoacetamide + thalido­mide) than the control group (iodoacetamide only). Histologi­cally, colonic inflammation in the treated group was markedly decreased.

Conclusions: Thalidomide effectively decreases colitis induced by iodoacetamide. The mechanism is probably associated with inhibition of TNFá, and should be further studied.
 

Objective: To study whether retinolpalmitate, beta-car­otene or lycopene could prevent liver cirrhosis induced by thioacetamide in rats.

Methods: In the control group liver cirrhosis was induced in male Wistar rats by intraperitoneal injections of TAA 200 mg/ kg for 12 weeks. The three study groups received in addition to TM either beta-carotene, lycopene or retinolpalmitate by gavage through an orogastric tube. Histopathological analysis and determination of the hydroxyproline contents of the livers were performed at the end of the protocol.

Results: Rats treated with beta-carotene and TAA had lower histopathologic scores and reduced levels of hepatic hydroxyproline (P= 0.02) than those treated by TAA alone. A trend of decreased fibrosis was observed in the rats treated with lycopene and TAA although this lacked statistical significance.

Conclusions: Beta-carotene attenuated liver cirrhosis induced by TAA in rats. The mechanism may be related to effects on hepatic stellate cells or to scavenging of free radicals by beta-carotene. Retinolpalmitate and lycopen had no significant beneficial effect.