Related Experiment Videos
Mural blood flow distribution in the large colon of horses during low-flow ischemia and reperfusion
1Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210-1089, USA.
Insights
This study investigated colonic blood flow changes during ischemia and reperfusion in horses. Microsphere measurements revealed significantly reduced blood flow in the large colon during low-flow ischemia.
Area of Science:
- Veterinary Medicine
- Surgical Research
- Cardiovascular Physiology
Background:
- Colonic ischemia and reperfusion injury is a critical concern in equine surgery.
- Accurate assessment of regional blood flow is essential for understanding tissue damage.
- Previous methods for measuring colonic blood flow in horses have limitations.
Purpose of the Study:
- To quantify colonic blood flow in horses during experimentally induced low-flow ischemia and reperfusion.
- To compare Doppler ultrasonic flowmetry with the microsphere method for assessing colonic blood flow.
Main Methods:
- Six horses underwent 3 hours of low-flow ischemia (20% of baseline) and 3 hours of reperfusion of the large colon.
- Colonic blood flow was continuously measured using Doppler ultrasonic flow probes.
- Tissue blood flow was determined using colored microspheres injected into the colonic artery.
- Biopsy specimens were collected at baseline, during ischemia, and after reperfusion.
Main Results:
- Doppler blood flow decreased to approximately 20% of baseline during ischemia.
- Microsphere measurements indicated colonic blood flow was reduced to 13.7–15.5% of baseline at 3 hours of ischemia.
- Significant reductions in mucosal, seromuscular, and full-thickness colonic blood flow were observed.
Conclusions:
- Low-flow ischemia significantly compromises blood flow to the equine large colon.
- The microsphere method provides a reliable assessment of regional colonic blood flow during ischemic events.
- Findings highlight the vulnerability of the equine colon to ischemic injury.
Abstract:
Six horses were subjected to 3 hours of low-flow ischemia and 3 hours of reperfusion of the large colon. After induction of anesthesia, the large colon was exteriorized through a ventral midline celiotomy. Colonic blood flow was measured continuously, using Doppler ultrasonic flow probes placed on the colonic arteries supplying the dorsal and ventral colons and was allowed to stabilize for 15 to 30 minutes after instrumentation. Low-flow ischemia was induced by reducing colonic arterial blood flow to 20% of baseline (BL) flow. Colonic mucosal, seromuscular, and full-thickness blood flow were determined on a tissue-weight basis by injecting colored microspheres proximally into the colonic artery supplying the ventral colon. Reference blood samples were obtained at a known flow rate from the colonic artery and vein at a site more distal to the site of injection. Left ventral colon biopsy specimens were harvested at BL, 3 hours of ischemia, and 15 minutes of reperfusion. Blood and tissue samples were digested and filtered to collect the microspheres, and dimethylformamide was added to release the colored dyes. Dye concentration in blood and tissue samples was measured by use of spectrophotometry, and tissue-blood flow was calculated. Data were analyzed, using two-way ANOVA for repeated measures; statistical significance was set at P < 0.05. Doppler blood flow decreased to approximately 20% of BL, whereas microsphere blood flow ranged between 13.7 and 15.5% of BL at 3 hours of ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)