| Objective The over-long arbitrary flap was designed on the back of rats to simulate the ischemic flap model,different interventions were performed on the flap through the hirudin group and the control group,Compare the flap survival area and the number of microvessels,tissue structure and inflammatory cell infiltration of the two groups under light microscope,At the same time,micro-ct and three-dimensional reconstruction technology were used to reproduce the flap microcirculation network,observe and measure the angiogenesis of the two groups of flaps by using the machine’s own software,and To investigate the effect of natural hirudin on angiogenesis of ischemic skin flap in rats from a microscopic and intuitive perspective.Methods Thirty-two healthy adult SD rats,male or female,with a body mass of 300±10g,were selected,a flap with a size of 8.0cm × 1.8cm was designed with the bilateral iliac spine line as the bottom edge and the posterior midline as the axis,numbered according to the sequence of surgery,and then randomly divided the rats into hirudin group and control group according to the random number table method,with 16 rats in each group.The two groups of rats were respectively marked with three points 2cm,4cm and 6cm from the bottom edge of the posterior median line.Rats in the hirudin group were subcutaneously injected with 0.1ml of natural hirudin every day at the above points immediately and within 3 days after surgery,and each rat was injected with 0.3 ml(including 6 ATU of natural hirudin).Rats in the control group were subcutaneously injected 0.1ml of normal saline at each point every day immediately after the operation and within 3 days after the operation,with a total of 0.3ml each time.At 6 days after the operation,the flap was roughly observed,and the back of the rat was photographed by digital camera with fixed focal length.The image was input into the computer.The survival rate of the flap was measured by Image pro-plus 6.0 software(Media Cybernetics,USA),(flap survival rate = Flap survival area / total flap area * 100%),Some rats were randomly selected for HE staining,and the histological changes of the flap were observed under light microscope and the number of microvessels was counted.Then,some rats were randomly selected for cardiac aortic puncture and successively injected with 10 U/m L heparin sodium saline,4% paraformaldehyde and 5% gelatin lead oxide mixture.After freezing,micro-CT detection and three-dimensional reconstruction observation and measurement of flap blood vessel volume,length and Quantity.Results Both groups of rats survived to the end of the experiment without infection.Different degrees of necrosis occurred in the distal part of the skin flaps in both groups at 6 days after the opertation,but the necrosis degree of the Hirudin group was lower than that of control group,the skin flap of Hirudin group has the significantly higher survival rate than the control goroup(P<0.05).Histological observation showed that the histological hierarchy of the hirudin group was clearer than that of the control group,with more microangiogenesis and less inflammatory response and inflammatory cell infiltration.Micro-CT 3D reconstruction showed that the flap vessels in the hirudin group were more and denser,and the volume,length and number of vessels were significantly higher than the volume,length and number of vessels in the control group(P<0.05).Conclusion Natural hirudin can reduce the inflammation of tissue,promote the regeneration and recanalization of blood vessels in ischemic flap,so as to improve the survival rate of the flap. |
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