Neutrophil (PMN) phagocytosis and chemotaxis after 2 hr of ischemia
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Published on: September 24, 2011
1Department of Surgery, Wadsworth VA, Los Angeles, California.
Abstract:
The role of PMN in the reperfusion injury after ischemia is unclear. It was the purpose of this study to determine if PMN functions of phagocytosis and chemotaxis were altered after a brief period of ischemia (2 hr) followed by reperfusion (1 hr) in a model where no 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 2 hr. 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 by PMN. The zymosan beads had been opsonized wtih baseline (b) (b), ischemia (i), or reperfusion (r) serum. 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. Results for phagocytosis demonstrated a significant increase in i and r PMN as compared to b PMN. Opsonization by b,i, or r serum did not enhance this effect (ANOVA, F = 4.477; P = 0.0266). Similar increases in chemotaxis were observed for i and r PMN which also were not enhanced by the chemoattractants of b, i, or r serum (ANOVA, F = 25.43; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Polymorphonuclear leukocytes (PMN) show increased phagocytosis and chemotaxis after ischemia and reperfusion, even without significant injury. These functions are not enhanced by serum opsonization or specific chemoattractants.
Area of Science:
- Immunology
- Vascular Biology
- Surgical Research
Background:
- The role of polymorphonuclear leukocytes (PMN) in ischemia-reperfusion injury remains incompletely understood.
- Investigating PMN function alterations is crucial for understanding tissue damage following blood flow restoration.
Purpose of the Study:
- To determine if PMN phagocytosis and chemotaxis are altered following a brief ischemic period (2 hours) and subsequent reperfusion (1 hour).
- To assess these PMN functions in a model where significant reperfusion injury did not occur.
Main Methods:
- Blood samples were collected from New Zealand white rabbits at baseline, after 2 hours of iliac and femoral artery clamping (ischemia), and after 1 hour of reperfusion.
- PMN phagocytosis was measured using zymosan opsonized with baseline, ischemic, or reperfusion serum.
- PMN chemotaxis was evaluated by quantifying PMN migration towards serum from baseline, ischemic, or reperfusion samples as chemoattractants.
Main Results:
- Phagocytosis by PMN significantly increased after both ischemia and reperfusion compared to baseline.
- PMN chemotaxis also showed significant increases following ischemia and reperfusion compared to baseline.
- Neither phagocytosis nor chemotaxis was enhanced by opsonization with different serum types or by specific chemoattractants from different time points.
Conclusions:
- PMN phagocytic and chemotactic functions are enhanced following a brief period of ischemia and reperfusion, independent of significant reperfusion injury.
- The observed alterations in PMN function are not modulated by serum opsonization or chemoattractants from ischemic/reperfused states.
- These findings suggest intrinsic changes in PMN function occur early after ischemia/reperfusion.
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