The increase of COX expression is one of the major markers of inflammation and, interestingly, in our study the contemporary treatment of D.I.O. zebrafish with 3,5-T2 sustained the enhancement of COX2 expression induced by D.I.O. This effect could be due to the alteration of mitochondrial number and oxidative function induced by chronic HFD and which can change with type of fat contained in the diet inducing obesity [49,50]. This evidence concerns the gene PTGS2 and obesity due to melanocortin 4 receptor deficiency.