An in vitro model for studying vascular injury after laser microdissection.

We have developed an in vitro model for studying vascular injury. After 7-10 days in a three-dimensional collagen gel culture, capillary-like tubes were formed in the collagen gels. We injured these capillary-like tubes with a laser microdissection system or a scrape method with razors and then examined the collagen gel culture by phase contrast and electron microscopy. After laser injury, profuse necrotic cells were observed around the injured capillary-like tubes and within the tubular lumen compared to the razor injury. We then isolated total RNA from these cultures and prepared cDNA for investigations by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). Quantitative real time RT-PCR revealed the up-regulation of transcription factor early growth response-1 (Egr-1) after both laser and razor injury, accompanied by the up-regulation of fibroblast growth factor-2 (FGF-2), a proangiogenic factor downstream of Egr-1. The effective laser energy is concentrated on the minute focal spot only. These methods provide a useful in vitro model for studying vascular injury.