Abundance of mRNA of growth hormone receptor and insulin-like growth factors-1 and -2 in duodenal and colonic biopsies of dogs with chronic enteropathies

Abstract

Repair processes of the inflamed intestine are very important for dissolution of chronic enteropathies (CE). Therefore, we examined the mRNA abundance of growth hormone receptor (GHR), insulin-like growth factors (IGF)-1 and -2 in duodenal and colonic biopsies of dogs with CE such as food-responsive diarrhoea (FRD) and inflammatory bowel disease (IBD) before and after treatment as compared with each other and healthy dogs. A clinical score (Canine IBD Activity Index = CIBDAI) was applied to judge the severity of CE. Biopsies of duodenum and colon from client-owned dogs with CE were sampled before (FRD bef, n = 5; IBDbef, n = 5) and after treatment (FRD aft, n = 5; IBDaft, n = 5). Intestinal control samples were available from a homogenous control population (n = 15; C). Intestinal samples were homogenized, total RNA was extracted, reverse transcribed and analysed by real-time polymerase chain reaction to measure mRNA levels of GHR, IGF-1 and IGF-2. Results were normalized with glyceraldehyde phosphate dehydrogenase as housekeeping gene. The CIBDAI decreased during the treatment period in FRD and IBD (P < 0.01). In duodenum, GHR mRNA levels were higher in all groups than in C (P < 0.001). Duodenal IGF-1 mRNA levels in FRD aft and IBDaft tended to be higher than in C (P < 0.1). The IGF-2 mRNA abundance in FRDaft was higher than in C (P < 0.05) in duodenum. In colon, mRNA levels of IGF-1 in IBDaft were higher than in FRDaft (P < 0.05) and levels differed between IBDaft and C (P < 0.05). In conclusion, mRNA levels of GHR, IGF-1 and IGF-2 in the gastrointestinal tract were increased during CE when compared with gastrointestinally healthy dogs. The data suggest that GHR, IGF-1 and IGF-2 are involved in gastrointestinal repair processes. © 2005 The Authors.