^aUniversity of Pittsburgh, Pittsburgh, PA

Available online 27 August 2008.

Article Outline

Introduction

Methods

Results

Conclusions

Introduction

Molecular hydrogen shows potential for reducing ischemia/reperfusion (IR) injury. We investigate the effect of hydrogen on intestinal IR injury.

 

Methods

Rodents were subjected to SMA clamp IR (50min) and reperfusion with air or molecular hydrogen (2%) inhalation (30 pretreatment/50min ischemia/30min posttreatment). Histochemistry and IHC on jejunal muscularis whole-mounts quantified neutrophil and F4/80+ monocyte recruitment into the muscularis externa (N=4 each). Organ bath recordings measured jejunal circular muscle contractility to bethanechol (0.3-300μM, N=6 each). Orally fed FITC-fluorescent microspheres (0.4μM) within muscularis leukocytes assessed mucosal barrier function.

Results

Few neutrophils were observe in air and hydrogen treated controls (Air=1.1±0.23 vs. Hydrogen=0.6±0.14). I/R resulted in a significant increase in neutrophils into the muscularis of air treated mice (46.2±8.19), which was significantly decreased by hydrogen inhalation (16.7±4.69). Monocytes were not observed within control tissues, but I/R air mice exhibited the appearance of dense monocytic plaques at 24 hours. Hydrogen treated animals did not exhibit the monocytic plaques. Bethanechol dose-response curves demonstrated no difference between air and hydrogen treated control mice or 3hrs after reperfusion. However, 24 hours after reperfusion hydrogen treatment resulted in markedly improved muscle contractility compared to air (Air-I50min/R24hrs=0.26±0.071 vs. Hydrogen-I50min/R24hrs=0.68±0.118 g/mm2/sec @ 100μM bethanechol). I/R resulted in a time dependent lumeno-lymphatic transference of microspheres in 30 minutes after reperfusion that was blocked by lymphatic ligation.

Conclusions

I/R injury causes a breakdown in mucosal barrier function, neutrophil and monocyte recruitment into the muscularis externa resulting in a suppression in muscle function, which is significantly prevented by molecular hydrogen.