Depot-specific mRNA expression by equine adipocytes

Introduction: Obesity in man and horses has been described as a state of low-grade inflammation characterised by elevated concentrations of circulating inflammatory markers. In horses, adipose tissue distributed specifically on the crest of the neck could indicate or contribute to hyperinsulinemia, insulin resistance or risk for laminitis. The purpose of the study was to compare mRNA expression between different equine adipose tissue depots and the influence of body condition score, using a reliable set of reference genes. Materials and methods: From 12 healthy geldings, euthanised for non-research purposes, adipose tissue samples were collected from neck (nuchal), intra-abdominal (mesenterial, right kidney, retroperitoneal) and subcutaneous (loin, tail head) fat depots. The horses were divided into 2 groups (n=6) according to their BCS: normal BCS (4-5/9) or overweight and obese BCS (7-8.5/9). Results and discussion: Reference gene expression stability and optimal number for normalization was evaluated with the geNorm algorithm. The genes ACTB, GAPDH, HPRT, RPL 32 and SDHA were identified as reference genes. No significant effect of body condition was found for any of the parameters evaluated (P>0.05). Leptin mRNA expression was higher in the three neck samples compared to the mesenteric adipose tissue samples (P0.05). Conclusions: Adipose tissue location is associated with differences in mRNA expression of the genes involved in inflammatory processes. These results suggest that individual differences in adipose tissue distribution may affect inflammatory status