Methods: The study included 32 male Sprague-Dawley rats (weight 242±26 g; age 9 to 11 weeks). Rats were divided into four equal groups: control group: no clamp was applied on abdominal aorta; group 1: plastic bulldog clamp was applied on abdominal aorta for 10 minutes; group 2: metal bulldog clamp was applied on abdominal aorta for 10 minutes; group 3: microvascular clamp was applied on abdominal aorta for 10 minutes. At the end of 10 minutes, segments occluded with vascular clamp were excised in all groups and endothelial structures were evaluated histopathologically.

Results: Normal cellular sequencing and structure were determined in control group. Most severe injury of the endothelial surface was observed in group 3, moderate level endothelial injury was observed in group 2, while mildest endothelial injury was observed in group 1. Increased vascular endothelial growth factor expression levels were detected histopathologically in groups 1 and 2 (2.8±0.5 and 3.3±0.5, respectively) when compared with the control subjects (2.0±0.5).

Conclusion: Due to their induced pressure and clamping force, vascular clamps may cause endothelial injury.