Restoration of the inflammatory gene expression by horse oil in DNCB-treated mice skin

The present study evaluated the anti-inflammatory effect of horse oil in 2, 4-dinitrochlorobenzene (DNCB)-treated BALB/c mice. After the application of DNCB, the mice showed atopic dermatitis symptoms, including severe erythema, hemorrhage, and erosion, whereas those symptoms were alleviated by treatment with horse oil. To explain the anti-dermatitis effect of horse oil, the gene expression levels in the healing process in dorsal skin were observed using a cDNA microarray. The cDNA microarray analysis revealed that the expression levels of 30 genes related to the inflammation, including Ccr1, Ccr2, Ccl20, Anxa1, and Hc genes, were up-regulated (higher than 2.0-fold) in the DNCB group compared to the levels in the control group, whereas the levels were restored to the control level in the DNCB + horse oil-treated group. In contrast, the gene expression levels of 28 genes related to inflammation, including chemokine genes Ccl5, Ccl7, Ccl8, Cxcl10, and Cxcl13 genes, were down-regulated (lower than 0.5-fold) in the DNCB group compared to the levels in the control group, whereas the levels were restored to the control level in the DNCB + horse oil-treated group. Overall, the results show that horse oil restores the expression levels of genes related to inflammation that were perturbed by DNCB treatment.