【Animal modeling】-Negative pressure sealing drainage combined with heparin lavage in the treatment of rabbit scald and seawater immersion wounds

  Objective: To observe the effect of negative pressure sealing drainage combined with heparin solution lavage on the healing of rabbit back scald combined with seawater immersion.

  Methods: Twenty New Zealand white rabbits were selected, and four 1% TBSA deep second-degree scald wound models were established on both sides of the spine. Sealed negative pressure suction therapy (group C), sealed negative pressure suction combined with heparin lavage after seawater immersion (group D). The wound exudation and necrosis were observed on the 1st, 3rd, 5th and 7th days after scalding, and the materials were collected for HE and immunohistochemical staining. The pathological changes of the wound and the expressions of vascular endothelial growth factor (VEGF) and cd31 were observed under light microscope, and the tissue vascular density was calculated. The morphological changes of wound capillaries and endothelial cells were observed under electron microscope. The tissue water content was calculated using the wet and dry weight method. On the 3rd, 5th, 7th and 14th days, the wound healing rate was calculated using millimeter square paper.

  RESULTS: Compared with the non-immersion group (group A), the wound surface after seawater immersion (group B) was dry, deepened, and had a high degree of edema. Compared with group B, the wounds of group C and group D had faster shedding of necrotic tissue, better basal blood supply, and the degree of early necrosis of wounds was lower than that of group B. After scalding, the water content of wound tissue in each group increased and reached the peak on the 3rd day, and the water content of wound in group B was the highest at each time point. The water content of groups C and D was lower than that of group B, and the difference was statistically significant. Light microscope and electron microscope observation showed that after scalding, the wounds in each group had inflammatory cell infiltration and different degrees of vascular basement membrane damage. In group B, the vascular endothelial cells in the wound were severely damaged and shrunken significantly. The accumulation of shrunken red blood cells and vascular embolism were the most obvious in the blood vessels. Obviously, the damage of the capillary basement membrane in group D was less, and the endothelial cell membrane was more intact. Scattered new blood vessels began to appear on the 3rd day after wound injury in each group. Group D appeared the earliest and had the highest peak value. Microangiogenesis in group B was late and the density was low.

  Conclusion: Negative pressure sealing drainage therapy combined with heparin solution wet compress therapy can effectively reduce the degree of tissue edema of scalded wounds after seawater immersion, improve tissue microcirculation, accelerate the removal of necrotic tissue, and promote the growth of new blood vessels. Effective means of burn wounds.