Action of larch bark in the regulation of cortisol induced stress in sheep

Abstract

The effect of Larix decidua (LD) dietary administration on gene expression patterns has been evaluated in sheep under ACTH challenge. Experimental protocol was approved by local laws and regulations. Eighteen sheep at maintenance were allotted to 3 groups: CTR (negative control, without ACTH, and supplementation), ACTH (positive control, with ACTH, and without supplementation), LD (ACTH and 50 g/head/day of LD). ACTH was injected for 3 subsequent days to ACTH and LD groups and blood was sampled before (T0) and after 3 (T3) and 51 (T51) hours from the first injection. RNA extracted samples were pooled together within group and time of sampling. A custom oligoarray was synthesized using 24,384 35 -40mer probes designed from 12,194 UniGenes (NCBI) on a CombiMatrix 90K platform. Cy5 labelled samples were hybridized on the chip. Statistical analysis, performed with MeV software 4.1 (TIGR), allowed the identification of a set of genes which were up or down regulated as a consequence of ACTH treatment. Genes that resulted differentially expressed were annotated with HomoloGene system and data mining was performed with Babelomics v3.1 tool. Functional analysis showed that most of the differentially expressed genes belong to KEGG pathways involved in immune system response and signaling molecules and interaction. Larch administration was effective in counteracting the effect of ACTH injection on the inflammatory processes, restoring the physiological homeostasis.