Analysis of peripheral blood mononuclear cells gene expression in endurance horses by cDNA-AFLP technique

The knowledge of molecular mechanisms of stress response in athlete horses can allow us to plan an appropriate and high-grade train- ing to obtain better performance and to preserve horse welfare. It is well known that excessive muscular exercise can lead to a number of responses which may be associated with modification of the mRNA levels for a number of metabolic genes such as those involved in the immune response. In the present study cDNA-AFLP technique was applied to Arab endurance horses under stressing conditions to visualise variations of transcriptional profiles; 49 transcript derived fragments (TDFs), differentially expressed, were cloned and sequenced. Four of these showed high sequence similarity with genes probably involved in exercise-induced stress response and resulted to be not sequenced in the horse. Their modulation was confirmed by RT-PCR and the full-length transcripts were isolated by RACE-PCR. The mRNAs sequences obtained were included in the GenBank database as Equus caballus interleukin 8 (IL8), E. caballus retinoblastoma binding protein 6 mRNA (RBBP6), E. caballus eukaryotic translation initiation factor 4 gamma 3 (eIF4G3) and E. caballus heat shock protein 90 (Hsp90). The expression pattern of these genes was verified in other endurance horses under stressing conditions, strengthen- ing the hypothesis of their real involvement in exercise stress-induced response.