Effect of apelin on mitosis, apoptosis and DNA repair enzyme OGG 1/2 expression in intestinal cell lines IEC-6 and Caco-2

Apelin is a regulatory peptide, identified as an endogenous ligand of the Apelin receptor (APJ). Both the apelin and the APJ were detected in brain, lung, heart, mammary gland, kidney, placenta, adipose tissues and the gastrointestinal tract. Apelin is considered an important regulatory gut peptide with a potential physiological role in gastrointestinal cytoprotection, regulation of food intake and drinking behaviour. The aim of the present study was to assess the effect of the apelin on mitosis, apoptosis and the expression of DNA repair enzyme (OGG 1/2), and APJ receptor in intestinal cell lines: rat crypt (IEC-6) and human enterocyte model (Caco-2). The cell cultures were incubated with the apelin-12 (10–8 M) for 4, 6, 12, 24 and 48 h and the apoptosis (caspase 3), mitosis (Ki-67) and DNA repair enzyme (OGG1/2) markers were studied by Real-Time qRT-PCR and immunofluorescent methods. The results of Real-Time qRT-PCR and immunocytochemical analysis showed that the levels of mRNAs were inversely related to the expression level of corresponding proteins. Immunofluorescent studies revealed inhibitory effect of apelin-12 on apoptosis, mitosis and the expression of OGG1/2 in the intestinal crypt cell line IEC-6. However, in the enterocyte model Caco-2 cells apelin stimulated apoptosis and mitosis, and reduced OGG1/2 expression. These findings suggest that apelin may be involved in the control of epithelial cell turnover in the gastrointestinal tract. (Folia Histochemica et Cytobiologica 2014, Vol. 52, No. 1, 51–59

Effects of L-alanyl-L-glutamine dipeptide administration during 35 days of postnatal life on intestinal mucosa, bone properties, and performance of piglets in their early post-weaning period

The experiment was performed on piglets, divided into control and experimental groups The experimental group received orally, from the birth to the 35(th) d of life, 0.4 g/kg b.w./d of L-alanyl-L-glutamine dipeptide (Ala-Gln). One week after weaning the piglets were killed and the small intestine and bones were sampled for histological analyses. Measurements of bone physical and geometric properties were performed according to Ferreti method. The mineral density was analysed by the DEXA method. Ala-Gln treated piglets had a higher body weight at the 35 d of age compared to that of the control piglets. Mucosa thickness, villus length, and crypt depth in the jejunum of the piglets showed higher values compared to controls. In Ala-Gln treated piglets bone physical and geometric parameters and mineral density were significantly higher, and the bone structure revealed a shift in its organisation and mineralization process. In conclusion, oral administration of Ala-Gln protects the piglets from body weight loss and intestinal hypotrophy correlated with weaning and preserved the normal development of the femora during the post-weaning period