Transcriptome modification of white blood cells after dietary administration of curcumin and non-steroidal anti-inflammatory drug in osteoarthritic affected dogs

The dietary effect of non-steroidal anti-inflammatory drug (NSAID) or curcumin on the gene expression of peripheral white blood cells in osteoarthritis (OA) affected dogs was investigated using a 44K oligo microarray. Two groups of OA dogs and one group of healthy dogs (6 dogs each) were clinically evaluated and blood was sampled before (T0) and after 20 days (T20) of dietary administration of NSAID (NSAID group) or curcumin (CURCUMIN group). Differentially expressed genes (P < 0.05) in comparison to the control group were identified with MeV software and were functional annotated and monitored for signaling pathways and candidate biomarkers using the Ingenuity Pathways Analysis (IPA). After 20 days of treatment, the differentially expressed transcripts significantly (P < 0.05) decreased from 475 to 173 in NSAID group and from 498 to 141 in CURCUMIN group. Genes involved in “inflammatory response” and in “connective tissue development and function” dramatically decreased at T20. Other genes, included in “cellular movement”, “cellular compromise” and “immune cell trafficking”, were differentially expressed at T0 but not at T20 in both groups. Specific molecular targets of CURCUMIN, not observed for NSAID, were the IkB up regulation in the “TNRF1 signaling pathway” and IL18 down regulation in the “role of cytokines in mediating communication between immune cells”. The activity of CURCUMIN was also evidenced from the inhibition of macrophages proliferation (HBEGF), related to a strong down regulation of TNFα and to activation of fibrinolysis (SERPINE1). The results would suggest that curcumin offers a complementary antinflammatory support for OA treatment in dogs.