Hui Li

Mentor:

Dr. Xinxin Ding

Department:

Pharmacology and Toxicology

Abstract:

Effect of arsenic exposure on HO-1 expression in mouse liver and small intestine

Objective: Environmental arsenic exposure is associated with various adverse health consequences in humans, including diabetes.  Previous studies found the high-dose single use of arsenic can increase the expression of several stress-related genes, particularly heme oxygenase-1 (HO-1), in mouse liver.  The aim of this study was to examine the effect of oral treatment with relative low doses of Arsenic on expression of HO-1 in the liver and small intestine and explore the mechanisms of the toxicities.  

Methods: C57BL/6J mice were treated with different doses of sodium arsenite (0, 2.5, 25, 50ppm) in drinking water for four weeks or treated with the same dose of sodium arsenite (25 ppm) for different days.  HO-1 gene and protein expression in the liver and intestine were monitored by quantitative real-time PCR and Western blot.

Results: HO-1 can be induced in mouse small intestine, but not in liver.  The induction of HO-1 was observed in small intestine when mice were treated with Arsenic at 25 ppm, and 50 ppm for four weeks.  As for the time-course study, HO-1 can be induced in small intestines from mice exposed to Arsenic for only 7 days.  Besides, the expression of HO-1 protein was higher in the proximal than in the distal small intestine.

Conclusions: Differential induction of HO-1 in response to arsenic in liver and intestine indicates different mechanisms and impact of HO-1 in different tissues.