| After the four weeks formal treatment, wounds which not healed are clinical defined as chronic wounds. Chronic wounds are characterized by whose healing process do not follow physiological procedures and self-sustaining in the excessive inflammatory response phase. The main causes of chronic wounds are trauma, burn, infection, ischemia and hypoxia, diabetes, high venous pressure and sustaining pressure on local tissue and so on. Many studies have shown that the of chronic wounds wound hypoxia and infection were prevalent in chronic wounds, both of which can significantly delayed wound healing. Topical oxygen pressure of chronic wounds center is usually around 5-20 mmHg; hypoxia of wounds can lead inflammatory cells and tissue repair cell oxidation for energy shortage, low metabolism, dysfunction or loss of vitality. Chronic wounds usually merge with advanced age malnutrition or other underlying diseases, resulting in immune function and wound maybe infected by pathogens. Serious infections caused cell apoptosis and inflammation persists; chronic wound repair is still the thorny issue. Vacuum sealing treatment, wash the wound, topical oxygen therapy are currently the more mature and effective means, but every single use is weak, its efficacy is certainly limited. Our previous study demonstrated that vacuum sealing drainage combined with oxygen and liquid irrigation can overcome the lack of a certain kind of technology, and complement each advantage, help with diabetic foot wound healing. In this study, people with chronic leg venous ulcer wounds and rabbits with chronic post-traumatic infectious wounds as research subjects, respectively pilot study and further explore the efficacy and mechanism of VSD combined with oxygen and liquid irrigation on chronic wounds;the technology was observed whether it promote the partial oxygen pressure of the wound more significantly, improve wound tissue capillaries and fibroblast proliferation, collagen deposition, alleviate infection and inflammation.Part OneEffects of vacuum sealing drainage combined with irrigation of oxygen loaded fluid on the growth of granulation tissue in chronic venous leg ulcersObjectiveTo evaluate the therapeutic effects of vacuum sealing drainage (VSD) combined with irrigation of oxygen loaded fluid on the growth of granulation and macrophage polarization in chronic venous leg ulcers.Methods34 patients with chronic venous leg ulcers hospitalized in our department from December 2010 to July 2014 were divided into group A (VSD group, n=11),group B (VSD+irrigation group, n=11) and group C (VSD+ oxygen loaded fluid irrigation group, n=12) according to the random number table. We performed debridement on the wounds after admission, and harvested the granulation tissue of wound center during the operation. And then, wounds in group A were treated with VSD only (negative pressure from -30 to-25 kPa, the same below); wounds in group B were treated with VSD combining with irrigation of normal saline; wounds in group C were treated with VSD combining with normal saline loaded with oxygen (flow of 1 L/min) irrigation. On post treatment day (PTD)7, all the VSD were removed. Then we detected the granulation tissue coverage rates and harvested some guanulation tissue of wound center. Wound gross observation was conducted before debridement and on PTD 7. HE staining and Masson staining was performed on the PTD 7 wound granulation tissue for histopathological observation, and expression of VEGF was detected by Immunohistochemistry. Before the negative pressure therapy and on PTD 7, transcutaneous oxygen pressure (TcPO2) of the skin around the wounds was measured by transcutaneous tissue oxygen tension survey meter; Cells with double positive expressions of induced nitric oxide synthase (iNOS) plus CD68 (type Ⅰ macrophage) and arginase 1 (Arg-1) plus CD68 (type Ⅱ macrophage) were observed and counted which stained by immunofluorescence. Data were processed with Fisher’s exact test, one-way ANOVA, LSD test, Paired sample t test, and covariance analysis.Results1. The gross observation of woundsThe gross observation of wounds showed that before debridement there was mass necrotic tissue, with a little edematous granulation tissue in all 3 groups. On PTD 7, new granulation tissue was found in all groups, and most in group C.That in group B was more than in group C.2. the granulation tissue coverage rate of woundsOn PTD 7, the granulation tissue coverage rate of group A, B and C were (76.9±4.2)%、(85.0±2.8)%、(88.6±3.8)%, respectively. It showed significant differences among three groups (F=30.73, P<0.01); The granulation tissue coverage rate of C group was higher than group A and group B (P<0.05 or P<0.01). That in group B was higher than in group C(P<0.01).3. Histopathological observation of woundsOn PTD 7, HE staining of the granulation tissue showed that more abundant new born capillaries and fibroblasts were observed in group C, while there were less newborn capillaries in group B and sparse newborn capillaries, fibroblasts and a little necrosis in group A.On PTD 7, the Masson staining of granulation tissue showed that there were more abundant newborn collagen in group C which distributed orderly and surrounded by a wealth of fibroblasts, while there was relatively fewer new collagen observed in group B which arranged loosely and distributed fairly evenly, and, there was sparse collagen in group A which arranged disorderly.4. Transcutaneous oxygen pressure (TcPO2) of the skin around the woundsOn PTD 7, TcPO2 of the skin around the wounds in group C [(40.7±4.1)mmHg] was higher than that in group A[(35.0±3.1)mmHg] and group B [(35.4±2.7)mmHg] (all P values below 0.01).There were no difference between group A and group B (P=0.35). TcPO2 of the skin around the wounds in three groups compared with that before treatment increased significantly (all P values below 0.01).5.The expression of VEGF in woundsOn PTD 7, the mean density of VEGF showed significant differences among three groups (F=11.85, P<0.01). The mean density of VEGF of the wounds in group C[(5.7±0.9)×10-3] was higher than that in group A [(3.9±0.8)×10-3] and in group B [(4.8±0.9)×10-3] (P< 0.05 and P<0.01, respectively), and, it was higher in group B than that in group A (P<0.05).6. The expression of TN F-a in woundsOn PTD 7, The expression of TNF-a of the wounds was decreased than before treatment, which in group C was lower than that in group A and in group B (P< 0.01), and, it was lower in group B than that in group A (P<0.01).7. The numbers of macrophages in granulation tissueOn PTD 7, the numbers of type I macrophages in granulation tissue of group A, B and C were 14.3±2.3/400×,11.5±3.0/400x,10.7±2.3/400x, respectively. It showed significant differences among three groups (F=25.14, P<.01), and the number in group C was less than that in group A and group B significantly (P<0.05 or P<0.01). Compared with that before treatment, the numbers of type I macrophages on PTD 7 in all 3 groups significantly decreased (t values range from 14.76 to 23.73, all P values below 0.01). On PTD 7, the numbers of type Ⅱ macrophages in granulation tissue of group A, B and C were 32.7±3.2/400x,35.1±3.3/400x,41.3±3.2/400x, respectively. It showed significant differences among three groups (F=81.10, P <0.01), and the number in group C was more than that in group A and group B significantly (all P values below 0.01). Compared with that before treatment, the numbers of type II macrophages on PTD 7 in all 3 groups significantly increased (t values range from -69.34 to -47.95, all P values below 0.01).ConclusionsVSD combined with oxygen and liquid irrigation can removing the necrotic tissues of the chronic venous ulcer effectively, correcting the state of hypoxia in wound tissues, making the activating state of macrophages transition from type I to type Ⅱ dominatingly, then, may promote the growth of granulation tissue.Part TwoEffect of vacuum sealing drainage combined with oxygen and liquid irrigation on chronic post-traumatic infectious wounds in rabbitsObjectiveTo evaluate the therapeutic effect of vacuum sealing drainage (VSD) combined with oxygen and liquid irrigation on the growth of granulation and the infectious status of chronic post-traumatic infectious wounds in rabbits; And further explore the mechanism of this technology in promoting the wound healing.Methods18 healthy conventional New Zealand Rabbits, each was made two 5 cm diameter circular full-thickness skin wounds on the back and fixed with plastic ring around the wound. After the cultivation of Staphylococcus aureus on the wounds and dressing four weeks later, they become models of chronic and difficult healing wounds. The rabbits were divided into group A (VSD group, n=6), group B (VSD+ irrigation group, n=6) and group C (VSD+oxygen loaded fluid irrigation group, n=6) according to the random number table. We performed debridement on the wounds, and harvested the granulation tissue of wound center during the operation. And then, wounds in group A were treated with VSD only (negative pressure from-30 to-25 kPa, the same below); wounds in group B were treated with VSD combining with irrigation of normal saline; wounds in group C were treated with VSD combining with normal saline loaded with oxygen (flow of 1 L/min) irrigation. On post treatment day (PTD)7, all the VSDs were removed. Then we detected the granulation tissue coverage rates and harvested some guanulation tissue of wound center. Wound gross observation was conducted before debridement and on PTD 7. HE staining and Masson staining was performed on the PTD 7 wound granulation tissue for histopathological observation. Before the negative pressure therapy and on PTD 7, transcutaneous oxygen pressure (TcPO2) of the skin around the wounds was measured by transcutaneous tissue oxygen tension survey meter; the quantitative detection of wound tissue by bacterial culture; and expression of TNF-a was detected by ELISA. Data were processed with Fisher’s exact test, one-way ANOVA, LSD test, Paired sample t test, and covariance analysis.Results1. The gross observation of woundsThe gross observation of wounds showed that before debridement there was mass necrotic tissue, with a little edematous granulation tissue in all 3 groups. On PTD 7, wounds were all narrowing; new granulation tissue was found in all groups, and most in group C, that in group B was more than in group C.2. Histopathological observation of woundsOn PTD 7, HE staining of the granulation tissue showed that sparse newborn capillaries, fibroblasts and a little necrosis were observed in group A, while there were more newborn capillaries and fibroblasts in group B; most abundant new born capillaries and fibroblasts in group C among 3 groups.On PTD 7, the Masson staining of granulation tissue showed that there was sparse collagen in group A which arranged disorderly, while there was relatively fewer new collagen observed in group B which arranged loosely and distributed fairly evenly; there was most abundant newborn collagen in group C among 3 groups which distributed orderly and surrounded by many fibroblasts.3. Transcutaneous oxygen pressure (TcPO2) of the skin around the woundsBefore treatment, TcPO2 of the skin around the wounds in 3 groups had no difference (P= 0.84). On PTD 7, TcPO2 of the skin around the wounds in 3 groups compared with that before treatment increased significantly (all P values below 0.01).TcPO2 of the skin around the wounds in group C was higher than that in group A and group B (all P values below 0.01). There were no difference between group A and group B (P=0.35).4. The tissue bacterial quantitiesBefore treatment, there was no difference in comparing the tissue bacterial quantities among 3 groups (P= 0.49). On PTD 7, log koc of tissue bacterial quantities was decreased, which in group C was lower than that in group A and in group B (all P values below 0.05), it was lower in group B than that in group A (P<0.01).5. The expression of TN F-a in woundsBefore treatment, the expression of TNF-a in the wounds showed no significant difference among three groups (P=0.59). On PTD 7, The expression of TNF-a of the wounds was decreased, which in group C was lower than that in group A and in group B (P< 0.01), and, it was lower in group B than that in group A (P<0.01).ConclusionsVSD combined with oxygen and liquid irrigation can promote the topical oxygen pressure effectively of chronic post-traumatic infectious wounds in rabbits, removing the necrotic tissues, alleviate the bacterial infection and inflammation reaction, stimulate wound tissue capillaries and fibroblast proliferation, collagen deposition and promote fresh wound granulation tissue proliferation. |
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