Effects of dexamethasone on small bowel and kidney oxidative stress and histological alterations in bile duct-ligated rats

Oxidative stress plays an important role in the pathogenesis of toxic liver diseases and other hepatic alterations including obstruction of bile flow. It has been shown that the gastrointestinal tract and renal tissue is particularly affected during obstruction of bile flow. In this study, we aimed to evaluate the effects of dexamethasone on small bowel and kidney oxidative stress and histological alterations in bile duct-ligated (BDL) rats. A total of 40 male Sprague-Dawley rats weighing 200-240 g were used in this study. Group 1 (Sham-control, n = 10) rats underwent laparotomy and bile duct was dissected from the surrounding tissue. Group 2 (Dexa-control, n = 10) rats underwent laparotomy and bile duct was dissected from the surrounding tissue. The rats received daily dexamethasone. Group 3 (BDL/Untreated, n = 10) rats were subjected to bile duct ligation and no drug was applied. Group 4 (BDL/Dexa, n = 10) rats received daily dexamethasone by orogastric tube for 14 days after BDL. At the end of the 2-week period, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were measured and biochemical and histological evaluation were processed. The mean serum bilirubin, liver enzymes, MDA level, and histopathological score significantly decreased and SOD, CAT, and GSH-Px values were significantly increased in group 4 when compared to group 3. Group 3 presented a significant increase in caecal count of E. coli and in aerobe/anaerobe ratio. In group 4, liver was moderately damaged. Ileal biopsies from group 4 demonstrated a significant increase in villus height, total mucosal thickness, and villus density when compared to group 3. Glomerular injury scores (GIS) and arterial injury scores (AIS) in group 3 rats were increased in the juxtamedullary region. In contrast to group 4, tubulo-interstitial lesions were diffuse in group 3 animals. Dexamethasone reduced small bowel and kidney oxidative stress and histological alterations in bile duct-ligated rats with increasing SOD, CAT, and GSH-Px and decreasing MDA levels in rats with obstructed bile duct.