Proceedings of The Physiological Society

Physiology 2016 (Dublin, Ireland) (2016) Proc Physiol Soc 37, PCA130

Poster Communications

The correlation between microbiota metabolic activity & mucosal homeostasis after ceftriaxone treatment

Y. Holota1, A. Bazan1, Y. Olefir1, N. Dzyubenko1, A. Ostapchuk2, T. Dovbynchuk1, T. Chervinska1, T. Serhiychuk1, A. Putnikov1, I. Kaji3, G. Tolstanova1

1. Educational and Scientific Centre "Institute of Biology", Taras Shevchenko National University of Kyiv, Kyiv, Ukraine. 2. D.K. Zabolotny Institute of Microbiology and Virology, Kyiv, Ukraine. 3. UCLA School of Medicine / CURE West LA VA Medical Center, Los Angeles, California, United States.

It is well established that compositional changes in the intestinal microbiota can lead to severe dysregulation of the physiological and immunological intestinal homeostasis with adverse consequences for the host, but mechanisms of this interaction are not fully understood. Recent studies suggest that products of microbial metabolism in the gut act as signaling molecules and influence host energy homeostasis (1, 2). According to epidemiological studies increasing exposure to antibiotics is associated with increased risk of developing multiple inflammatory disorders (3). Here we investigated whether and how antibiotic-induced disturbance in microbiota composition and its metabolic profile may affect the functional state of colon mucosa cells. Methods: Male Wistar rats (n=16, 140-160 g) were treated for 14 days with broad-spectrum antibiotic ceftriaxone (Cf) (300 mg/kg, i.m.) or vehicle; euthanized by CO2 inhalation followed by cervical dislocation next day after Cf withdrawal. The study was approved by the bioethical committee of Taras Shevchenko National University of Kyiv (Protocol No 8 issued by Nov 2, 2015). The parietal microbiota was analyzed by bacteriological culture methods; faecal short chain fatty acids (SCFA) - by gas chromatography; colonic localization and levels of FFA2 & FFA3 receptors and MCT1, MCT4 & SMCT1 transporters of SCFA - by immunohistochemistry, levels of Erk1/2, p38, Egr-1, Sp-1 and Hif-1α proteins - by Western blot analysis, superoxide dismutase (SOD) activity - by zymography method; catalase activity - colorimetrically. Results: Cf injection leads to increase the level of Propionibacterium and Bacteroidetes 1.6, 2.7-fold (p<0.05) respectively. Despite that the absolute amount of SCFA, levels of butyrate, propionate, acetate were decreased by 5.1, 9.3, 15.0, 2.7-fold (p<0.05), respectively. FFA2 receptors were localized on the goblet cells and surface enterocytes; FFA3 receptor - on surface enterocytes and in myenteric ganglia in the colon; MCT1 and MCT4 transporters - on the epithelial basolateral membrane surface and crypts enterocytes, SMCT1 - in the brush border of enterocytes. Cf administration decreased the immunoreactivity for FFA2 & FFA3 receptors and SMCT1 transporter but increase the MCT1 and MCT4 transporters. These changes were accompanied by the increase of Erk1/2 and decrease p38 MAP kinases activity in colon mucosa. Cf administration also decreased the activity of SOD and catalase antioxidant enzymes 1.4-fold (p<0.05) and increased levels of redox-sensitive transcriptional factors Egr-1, Sp-1 - 1.3-fold & Hif1α - 2-fold (p<0.05). Conclusions: Antibiotic-induced changes in SCFA amount and number of specific receptors and transporters to them evoked a significant shift in colonic mucosal homeostasis.

Where applicable, experiments conform with Society ethical requirements