Low Flow versus No Flow: Ischaemia Reperfusion Injury Following Different Experimental Models in the Equine Small Intestine.
Authors: Grages Anna Marei, Verhaar Nicole, Pfarrer Christiane, Breves Gerhard, Burmester Marion, Neudeck Stephan, Kästner Sabine
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Ischaemia Reperfusion Injury in Equine Small Intestine Models Researchers investigating strangulating small intestinal lesions in horses have used different experimental ischaemia models with inconsistent results, prompting this comparative study of low flow (80% reduction) versus no flow (100% occlusion) injury during 120 minutes of jejunal ischaemia followed by reperfusion in seven warmbloods per group. Using Laser Doppler fluxmetry, spectrophotometry, histological examination, immunohistochemistry and functional Ussing chamber analysis, the team identified markedly lower and more consistent tissue oxygen saturation in the no flow model, whilst the low flow group exhibited high variability with significantly greater haemorrhage at all time points despite being theoretically more representative of clinical disease. Both models showed increased inflammatory markers (cleaved-caspase-3 and calprotectin) during reperfusion, though no flow ischaemia resulted in significantly higher tissue conductance changes post-reperfusion, suggesting greater mucosal barrier dysfunction. For practitioners, these findings clarify that whilst low flow conditions may better mimic naturally occurring strangulation, the no flow model produces more reproducible and measurable ischaemia reperfusion injury, making it the superior choice for experimental research aimed at developing treatment protocols. Future clinical studies investigating novel therapies for strangulating colic should consider this distinction when extrapolating experimental findings to field cases.
Read the full abstract on PubMed
Practical Takeaways
- •When treating strangulating small intestinal lesions, understand that reperfusion injury involves complex inflammatory and apoptotic cascades that manifest differently depending on severity of initial blood flow compromise
- •Research findings suggest future experimental models should use no-flow conditions for more reproducible results, though clinical cases likely present with varying degrees of partial flow obstruction
- •Monitor post-operative intestinal tissue for markers of reperfusion injury (mucosal damage, increased inflammatory cells) as both partial and complete flow interruption trigger similar damaging pathways
Key Findings
- •No flow (NF) ischaemia produced significantly lower tissue oxygen saturation compared to low flow (LF) ischaemia
- •Low flow model showed high variability in oxygen saturation and greater mucosal damage with more haemorrhage at all time points
- •Both groups showed increased cleaved-caspase-3 and calprotectin-stained cells during reperfusion, indicating apoptosis and inflammation
- •No flow model produced more consistent ischaemia reperfusion injury patterns despite low flow being more clinically representative of strangulating disease