| Objective:The experiment copy SD rats animal model of pressure ulcers,discuss the role of different pressure form (vertical pressure, friction and shear force) to the influence of pressure ulcers. Ob serve pressure ulcer rat skin and muscle tissue in the naked eye and pathology changes; determination rats serum SOD, nitric oxide (NO) and malondialdehyde (MDA) content.For its into pressure ulcer risk factors assessment form and give corresponding to provide theoretical basis for the score.Methods:32SD rats male and female unlimited, supine in the cart before the horse after anesthesia glass syringes pressure device. This device will be hollow glass tube with a tourniquet with glass syringes empty tube connected. Add water within the device, the pressure generated by the stream through the piston but action at syringe rats knee bone long axon hind legs in skin tissues. Here is the skin tissue pressure parts. Through the calculation of the pressure parts area and the weight of the pressure, make the skin tissue is9kPa.32SD rats will randomly divided into4groups rats:the control group (group A), rats on the board, without any inflict any pressure7.5hours to death; the vertical pressure group (group B), pressure parts to vertical pressure2h and relax0.5h; friction group (group C), pressure parts to vertical pressure2h and in the end of2h with cotton cloth rub roundly, friction distance to1cm, and relax0.5h; shear force group (D group), the hind legs rats with glue stick to pressure parts limbs far end to drag the0.3-0.5cm, and oppression here skin tissues2hand relax0.5h;each group is given three ischemia (oppression2h)-reperfusion (relax0.5h) cycle was put to death.Macroscopic observation rat skin integrity and pressure parts color changes.In light-microscopy pressure parts of the skin and muscle tissue pathology, and the SOD activity,MDA and NO content.Results:1.Visual inspection:The skin of group integrity, and there were no significant differences before and after the experiment;the skin of Group B also integrity,compared with the experimental before skin appear purplish red;group C in the friction caused by skin redness and patch damaged;group D with the experiment than skin color before for dark red.2.Examine under the light microscope:The epithelial of group A presented clear,it’s complex layer squamous epithelium. The muscular fiber alined closely and the cross striation was clear. The epithelial of group B was thinner than that in group A.In group B,the structure levels appeared a little vague.The muscular tissue exhibited cell edema and and blurred cross striation.The epithelial of group C was thinner than that in group B.The structure level appeared a little vague and the cross striation was broken.The epithelial of group D was thin,the structure level appeared was vague.The muscular fiber was edema than group B.The naked eye pressure parts and optical microscope all appear damage, shear force group of muscle damage than vertical pressure groups more obvious; friction group of skin damage than vertical pressure group are more obvious.3.The activity of SOD, the content of NO and MDA was significantly difference in group B,C,D than that in group A.The activity of SOD was significantly lower(P<0.05), the content of NO was significantly lower (P<0.05)and the content of MDA was significantly higher(P<0.05) in group C than that in group B.The activity of SOD was significantly lower(P<0.01), the content of NO was significantly lower (P<0.01)and the content of MDA was significantly higher(P<0.01) in group D than that in group B.The activity of SOD was significantly lower(P<0.05), the content of NO was significantly lower (P<0.01)and the content of MDA was significantly higher(P<0.05) in group D than that in group C.Conclusions:1.Ischemia-reperfusion injury caused cells damage and lead to pressure ulcer.2.Shear force mainly cause deep tissue damage.3.The vertical stress mainly cause skin tissue damage.4.The vertical pressure, friction and shear force can be integrated into pressure ulcer risk factors assessment, and pass to increase score table. |
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