In vitro and in vivo responses of mucosa from the large colon of horses to ischemia and reperfusion.

The researchers focused on examining the effects of restricting and subsequently restoring blood flow (ischemia and reperfusion) on the large colon mucosa of horses. Their work established that quick ischemia could cause a rapid repair and full recovery of the colonic tissue during reperfusion, hence no injury due to reperfusion was noticed.

Methodology

• The study used six healthy horses. These horses were anesthetized and then put through a process of ischemia for 60 minutes at the pelvic flexure, and this was followed by reperfusion for 240 minutes.
• The colonic mucosa from ischemic (4 horses), reperfused (6 horses), and adjacent control horses (6) were isolated for in vitro testing and histological examinations.
• The tissues were mounted in Ussing chambers. These chambers were filled with plain Krebs Ringer bicarbonate (KRB), KRB with N-acetylcysteine (NAC), or KRB with a modified organ transplant solution (MOTS).
• To measure the integrity of the mucosa, they used transepithelial electrical resistance (TER) and mannitol flux. They analyzed the data using ANOVA and Kruskal-Wallis statistical tests.

Results and Conclusions

• The TER in reperfused tissues was found to be similar to the TER in control tissues, and greater than the TER in ischemic tissues. This was consistent with the morphological observation of recovery in reperfused tissues.
• The study also found that mannitol flux was greater in ischemic tissues than it was in reperfused tissues.
• Incubation of mucosa with NAC or MOTS did not significantly affect the TER and mannitol flux.
• The researchers concluded that ischemia caused during the short period allowed fast mucosal repair and complete recovery of tissue barrier properties during reperfusion. This led to the conclusion that there was no observable reperfusion injury for this method of ischemic damage in equine colonic mucosa.