| Objective: This study was aimed to explore the effects of two different values of oxygen flow combination with intermittent closed negative pressure drainage on rabbit ear ischemic wound.The comparative study of the wound model was prepared through various treatment methods,To improve the correlation between oxygen concentration and wound healing,provide further experimental evidence for improving the ability of repair chronic refractory wound.Methods : Twelve healthy rabbits were randomly selected from the experimental animal center of southwest medical university,male or female,and the age can be fromthree month tofour month old.Binaural back hair must be removed,disinfected and narcotized.The central artery and the brachial artery were ligated.Keep tail artery and all veins.the epidermis and dermis were removed by 2 x 2cm from the ear of rabbit,the ischemic wound was prepared bypreservation of perichondrium and some subcutaneous tissues.The 24 wounds were randomly divided into 6 groups.Group A: blank control;Group B:(oxygen flow 2L/min);group C:(oxygen flow 5L/min);group D: simple negative pressure;group E: topical oxygen therapy and negative pressure wound therapy(oxygen flow 2L/min);group F: topica loxygen therapy and negative pressure wound therapy(oxygen flow 5L/min).The Adjustable negative pressure mode is set to intermittent negative pressure(5 minutes for work,2 minutes for pause),and negative pressure value is75 mmHg.On the 5th,7th,10 th and 14 th days after operation,the area of wounds in each group was measured with Image-Pro Plus 6.0 version image analysis software.The wound healing rate was calculated according to the formula.The specimen samples from the center and the edge of the wound were harvested at the corresponding time point,HE staining was used to observe the distribution of tissue neovascularization and collagen fiber.Both the expression of platelet-derived growth factor mRNA and the expression of interleukin-6 mRNA were detected by RT-PCR.Immunohistochemistry was used to determine the expression of Hypoxia inducible factor 1-alpha.Results: 1?Wound healing rate: the treatment groups were significantly higher than group A.there were statistically significant differences between each group(P(27)0.05).The wound healing rate of group D on5.7.10.14 was(45.65±0.95?57.16±0.71?82.75±3.31?94.1±1.32).The wound healing rate of group B on5.7.10.14 was(38.19±0.51?41.69±0.92?68.56±0.50?87.03±0.59).The wound healing rate of group C on5.7.10.14 was(41.48±1.60?43.36±0.84?71.72±1.79?89.16±1.01).There were statistically significant differences in group D and group B and group C at each time point(P(27)0.05).There were statistically significant differences in group B and group C at each time point(P(27)0.05).The wound healing rate of group Eon5.7.10.14 was(50.99±1.09?64.58±0.89?88.55±0.21?97.12±0.83).The differences were statistically significant in group D and group E at each time point(P(27)0.05).The woundhealing rate of group Fon5.7.10.14 was(54.29±0.48?67.70±2.39?89.57±0.40?98.34±0.35).The differences were statistically significant in group D and group F at each time point(P(27)0.05).The differences were statistically significant in group E and group F at each time point(P(27)0.05).The order of wound healing rate in each group: Group F was the fastest,group E and group D were second,group B and group C were slower,group A took the longest.2.Histological observation: HE staining showed that neonatal capillaries and collagen fibers of group A were the least,group B and group C were followed by group A,In group D,there were more newborn capillaries than in group B and group C.Partial capillary vessel wall is incomplete and collagenous fibers are disorderly arranged.The capillaries and collagen fibers both in group E and groupF were abundant.the newborn capillaries were filled with red blood cells in group F and collagenous fibers are arranged regularly.The expression order of each group: group F(29)group E(29)group D(29)group B and group C(29)group A.3.The expression of wound PDGFmRNA: Different treatment groups compared with blank control group were statistically significant(P(27)0.05),There was no significant difference between the group B and the group C(P(29)0.05),The differences were statistically significant in group D and group E at each time point(P(27)0.05).The differences were statistically significant in group D and group F at each time point(P(27)0.05).The differences were statistically significant in group E and group F at each time point(P(27)0.05).The expression order of each group: group F(29)group E(29)group D(29)group B and group C(29)group A.4.The expression of wound IL-6 mRNA : Different treatment groupscompared with blank control group were statistically significant(P(27)0.05),There is no difference between the group B and the group C(P(29)0.05),The differences were statistically significant in group D and group E at each time point(P(27)0.05).The differences were statistically significant in group D and group F at each time point(P(27)0.05).The differences were statistically significant in group E and group F at each time point(P(27)0.05).The expression order of each group: group F(29)group E(29)group D(29)group B and group C(29)group A.5.Immunohistochemistry: Image-pro Plus6.0 map Image analysis software was used to measure the expression of HIF1 – ? of each group.the expression level of HIF1 – ? protein of groupB on5.7.10.14 days was(0.36±0.06?0.27±0.03?0.24±0.02?0.18±0.03).the expression level of HIF1– ? protein of groupA on5.7.10.14 days was(0.43±0.05?0.31±0.02?0.27±0.03?0.24±0.03).The differences were statistically significant in group Band group A at each time point(P(27)0.05).the expression level of HIF1 – ? protein of groupC on5.7.10.14 days was(0.34±0.04?0.24±0.03?0.22±0.02?0.18±0.01)The differences were statistically significant in group Cand group A at each time point(P(27)0.05).There is no difference between the group B and the group C(P(29)0.05).the expression level of HIF1 – ? protein of groupD on5.7.10.14 days was(0.53±0.03?0.39±0.08?0.33±0.05?0.27±0.04).the expression level of HIF1 – ? protein of groupE on5.7.10.14 days was(0.47±0.05?0.35±0.03?0.29±0.05?0.24±0.04).the expression level of HIF1 – ? protein of Group F on5.7.10.14 days was(0.40±0.06?0.28±0.03?0.24±0.05?0.22±0.06)The differences were statistically significant in group D and group A at each time point(P(27)0.05).The differences were statistically significant in group D and group E at each time point(P(27)0.05).The differences were statistically significant in group D and group Fat each time point(P(27)0.05).The differences were statistically significant in group E and group Fat each time point(P(27)0.05).The expression order of each group: group D(29)group E(29)group A(29)group F and group B(29)group C.Conclusion: Intermittent negative pressure closed drainage combined with topical oxygen therapy is complementary to the repair of rabbit ear ischemic wound.TOT(oxygen flow value 5L/min)+ intermittent negative pressure closed drainage(negative pressure value-75 mmHg,attracting 5min,stopping 2min)was superior to the remaining treatment group,increasing the healing rateof the wound.The mechanism may be by improving the hypoxic environment of the wound surface,to promote the regeneration of neovascularization and collagen deposition of the wound,it was associated with up-regulation of PDGFmRNA expression,down-regulation of HIF 1-alpha protein expression and down-regulation of IL-6m RNA gene expression. |
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