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Neutrophil (PMN) phagocytosis and chemotaxis after reperfusion injury
1Department of Surgery, Wadsworth VA Medical Center, Los Angeles, California.
Abstract:
Neutrophils (PMN) have been implicated as mediators of the reperfusion injury which occurs in skeletal muscle after ischemia. This study was performed to measure PMN phagocytosis and chemotaxis after 3 hr of ischemia followed by 1 hr of reperfusion in a model where a significant reperfusion injury occurred. Baseline blood samples were drawn from an ear artery from New Zealand white rabbits for PMN and serum. The right iliac and femoral arteries were clamped for 3 hr which resulted in a severe clinical reperfusion injury. Just prior to clamp release, blood was harvested from the right iliac vein. After 1 hr of reperfusion, blood was again harvested from the right iliac vein. Phagocytosis was measured by the percentage ingestion of zymosan beads by the PMN. The zymosan beads had been opsonized with baseline (b), ischemia (i), or reperfusion (r) serum. Results for phagocytosis revealed no difference for (b) PMN when opsonized by (b), (i), or (r) serum. A significant increase was seen in (i) PMN phagocytosis when (i) or (r) serum was present. Also, a significant increase in (r) PMN phagocytosis was seen when (i) serum was present (ANOVA: F = 14.47; P = 0.0002). Chemotaxis was evaluated by the number of PMN migrating across a filter. Serum obtained from (b), (i), and (r) blood samples served as the chemoattractants. Significant increases in chemotaxis were observed for (b), (i), and (r) PMN when (i) serum was used as the chemoattractant (ANOVA: F = 7.11; P = 0.0025). We conclude: (1) Rabbit PMN harvested after ischemia and reperfusion demonstrated increased phagocytosis when (i) serum was present.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Neutrophils (PMN) show increased phagocytosis after ischemia and reperfusion, especially when exposed to ischemia serum. This suggests PMN function is altered, impacting skeletal muscle reperfusion injury.
Area of Science:
- Immunology
- Physiology
Background:
- Neutrophils (PMN) are implicated in skeletal muscle reperfusion injury following ischemia.
- Understanding PMN function during ischemia-reperfusion is crucial for mitigating tissue damage.
Purpose of the Study:
- To quantify neutrophil phagocytosis and chemotaxis in a rabbit model of skeletal muscle ischemia-reperfusion injury.
- To investigate the impact of ischemia and reperfusion on PMN function.
Main Methods:
- Induction of 3-hour ischemia followed by 1-hour reperfusion in New Zealand white rabbits.
- Measurement of PMN phagocytosis using opsonized zymosan beads.
- Assessment of PMN chemotaxis across a filter with different serum chemoattractants.
Main Results:
- Neutrophil phagocytosis significantly increased when neutrophils from ischemic or reperfused states were exposed to ischemic or reperfusion serum.
- Neutrophil chemotaxis significantly increased when using serum from the ischemic period as a chemoattractant.
- Baseline neutrophils did not show altered phagocytosis with different serum types.
Conclusions:
- Neutrophils harvested after ischemia and reperfusion exhibit enhanced phagocytic activity in the presence of ischemic serum.
- Ischemia and reperfusion significantly alter neutrophil function, contributing to skeletal muscle injury.
- Neutrophil chemotaxis is also elevated when exposed to serum from the ischemic phase.