Hydrogen sulfide attenuates ischemia-reperfusion injury in in vitro and in vivo models of intestine free tissue transfer

BACKGROUND: Ischemia-reperfusion injury is the propagation of injury following reintroduction of oxygen to previously ischemic tissue. The purpose of this study was to evaluate whether hydrogen sulfide provides protection against ischemia-reperfusion injury in enteric tissue. METHODS: In vitro (enterocyte anoxia-normoxia) and in vivo (rat intestinal ischemia-reperfusion) models of ischemia-reperfusion injury were tested with or without the addition of hydrogen sulfide. Apoptotic index was determined in vitro, and gross appearance, histology, and villus height (a measure of mucosal integrity) were assessed in vivo. Statistical analysis was performed, and significance was defined as p < 0.05. RESULTS: In vitro, cells treated with 10 μM hydrogen sulfide after 1-hour anoxia experienced a significant decrease in apoptotic index compared with untreated control (0.5 ± 0.3 percent versus 2.8 ± 0.7 percent); after 3 hours of anoxia, cells treated with 1 μM, 10 μM, and 100 μM hydrogen sulfide experienced significant decreases in apoptotic index versus untreated control (1.6 ± 0.8 percent, 1.8 ± 0.9 percent, and 2.8 ± 0.7 percent versus 8.6 ± 1.7 percent). In vivo, intestine treated with [10 μM] or [100 μM] hydrogen sulfide retained normal coloration and villus architecture after 1-hour ischemia; after 2 hours of ischemia, only intestine treated with [10 μM] hydrogen sulfide appeared uninjured. After 1, 2, or 3 hours of ischemia, villus heights of intestine treated with [10 μM] or [100 μM] hydrogen sulfide were significantly higher than heights of non-hydrogen sulfide-treated villi. CONCLUSIONS: Hydrogen sulfide significantly attenuates ischemia-reperfusion injury in intestinal tissue in vitro and in vivo. These results have significant implications for enteric free tissue transfers and other gastrointestinal procedures in which ischemic intervals may be anticipated.