Effect of high-molecular weight dextran macromolecules on low-flow ischemia and reperfusion of the large colon in horses.

This study analyzes the impact of high-molecular weight dextran molecules on the large colon’s low-flow ischemia and reperfusion in horses. The results indicate that while high-molecular weight dextran did not harm the colonic mucosa or alter systemic hemodynamic or metabolic aspects, it failed to protect the colonic mucosa from the effects of low-flow ischemia and reperfusion.

Research Methodology

• The research involved 12 adult horses, divided into two equal groups.
• The first group was treated with 0.9 NaCl, while the second group received high-MW dextran solutions.
• All horses were subjected to low-flow ischemia for 3 hours, followed by 3 hours of reperfusion.
• Thirty minutes prior to reperfusion, either 0.9% NaCl or a 6% solution of high-MW dextran was administered intravenously.
• Hemodynamic measurables were recorded every half hour. Additionally, systemic arterial and colonic venous blood were collected for analysis, including determination of PCV, plasma total protein, and whole blood lactate concentrations.
• Also, large-colon biopsy specimens were examined histologically.

Results Summary

• The study found that the mean arterial pressure was higher in horses treated with high-MW dextran from 3 to 3.25 hours but didn’t vary significantly for any other hemodynamic parameters.
• Compared to initial values, colonic blood flow dropped significantly from 0.5 to 3 hours and rose significantly from 3.25 to 6 hours.
• Arterial and colonic venous PCV noted lower than baseline values during certain periods in the horses treated with high-MW dextran, indicating a significant difference in group-2 horses for specific time frames.
• Mucosal necrosis, hemorrhage, edema, and neutrophil infiltration were found in horses from both groups, but there was no significant distinction between the two sets.

Conclusions

• The research concluded that high-MW dextran did not protect the colonic mucosa from the effects of low-flow ischemia and reperfusion. Moreover, no adverse effects on the colonic mucosa or on systemic hemodynamic or metabolic variables were observed.
• Considering the findings, the research suggested that using high-MW dextran solution for reperfusion probably wouldn’t protect the large colon from the damages resulted by ischemia-reperfusion injury connected with large-colon volvulus.