STW 5 prevents stress-induced changes in intestinal permeability in mice in-vivo

The fixed-combination herbal preparation STW 5 (Iberogast) has been reported to increase intestinal chloride secretion in-vitro. However, the ability of STW 5 to modulate paracellular and transcellular permeability remains currently unknown. Therefore, we aimed to study the ability of STW 5 to modulate intestinal permeability under basal and repeated acute stress conditions.

C57-bl6 mice were gavaged for 14 days with STW 5 (3 mL/kg). After 10 days of treatment, mice were subjected to water avoidance stress (WAS) during 4 consecutive days. In-vivo permeability to FITC -Sulfonic Acid (FSA, 400 Da) and Horse Radish Peroxydase (HRP, 44KDa), total transit time and colonic transit (fecal pellet output – FPO) were assessed at Day 0 (D0), D10 and D14 of IB treatment. Ex vivo permeability to FSA and HRP was assessed on jejunum, ileum, proximal colon and distal colon at D14 using Ussing chambers. Corticosterone blood level was measured at D11 and D14.

In-ivo permeability to FSA and HRP as well as total transit time were not modified by STW 5 in basal and WAS conditions. However, STW5 prevented the increase in permeability to FSA induced by WAS in the distal colon ex vivo. Conversely, STW 5 prevented the increase in permeability to HRP induced by WAS in the jejunum and proximal colon. Furthermore, while STW 5 tended to increase colonic transit as compared to control in basal conditions, it prevented the increase in colonic transit induced by WAS. Finally, STW 5 did not modify the changes in corticosterone induced by WAS.

Our study suggests that STW 5 can prevent WAS induced changes in paracellular and transcellular permeability in specific regions of the gastrointestinal tract. Such effects could contribute to the therapeutic effects of STW 5 in irritable bowel syndrome and support novel therapeutic indications for pathologies in which barrier functions are altered.