Osteochondrosis-Related Gene Expression in Equine Leukocytes Differs among Affected Joints in Foals

Osteochondrosis (OC) is a developmental disease in horses with a significant impact on the horse’s welfare and
performance. Previously, differentially expressed genes in leukocytes of OC-affected have been identified and were
differentially expressed in horses of different ages when compared to their age-matched controls.As the time course
of the development of OC lesions seems to be joint dependent,the aim of this study is to compare in young OCaffected
horses (between 8 to 12 months), the different expression of selected genes depending the joints
involved.The expression of OC-related genes were analysed by rt-PCR and subsequent statistical analysis (ΔΔCT)
in the leukocytes of 30 Belgian Warmblood horses aged between 8 to 12 months divided in groups depending the
affected joints (fetlock, hock and stifle).In the three groups, expression of ApoB-3G, MGAT4A, B4GALT6 and
PRKCG genes were significantly higher in the OC-affected foals compared to the healthy foals. Based on the
profiles of expression ofApoB-3G, Dsh1/Dvl1, Foxl1, Hp, ISG15, Mark2, PPR2A, RUSC2 and WASH1 genes,the
localization of the disease can be determined: expression levels of ApoB3G, WASH1 and FOXl1 to identify fetlock,
ApoB3G, PPR2A to identify OC-development in the hock and ApoB3G, Dsh1/Dvl1, WASH1, PPP2R1A and Mark2
geneto identify OC-development in the stifle. However at this moment, the rt-PCR analysis of the identified genes as
biomarkers gives only diagnostic information. For the future, the profile of expression of these genes could give also
some predictive information on the evolution of the disease such as remission or permanent OC-lesions.