Gene expression profiling in small intestine of mice administered lactoperoxidase

Lactoperoxidase (LPO) is a component of milk and other external secretions. Recently, we found antiinflammatory effect of orally administered LPO in mouse model of influenza virus-induced pneumonia. In order to study influence of bovine LPO on the digestive tract as its possible target organ, we performed comprehensive gene expression analysis of the mouse small intestine using GeneChip microarray to compare the effect of LPO with that of water or bovine serum albumin (BSA). We observed that 3 h after single ingestion of LPO the levels of 78 gene expression are upregulated and those of 9 gene expressions are downregulated. Within most changed genes, 5 upregulated and 1 downregulated genes such as FK506 binding protein 5 (FKBP5) and serum/glucocorticoid regulated kinase (SGK) are known to be transcriptionally modulated by glucocorticoid. This result suggests that ingested LPO modulates gene expressions in the small intestine in a glucocorticoid-like manner and this activity may link to its systemic antiinflammatory effects. Keywords: treatment comparison Mice were orally administered 200 microL of water (n=3), bovine serum albumin (BSA, 2.5 g/kg body weight, n=3), or bovine lactoperoxidase (LPO, 2.5 g/kg body weight, n=3). Three hours after administration, comprehensive gene expressions of jejunum detached payer's patch were analysed for comparison of LPO administration with water or BSA administration.