| Background and purposeDiabetic ulcer is one of the serious complications of diabetes.Diabetic ulcer is difficult to treat,has been a major challenge in clinical work,often lead to amputation,even death.There are problems such as the slow of epithelium and the damage of blood vessel or nerve in patients with diabetic ulcer.It is necessary studying on healing mechanism of diabetic chronic ulcer,finding a key factor in promoting the wound healing,seeking a economic and effective treatment.The previous research of our group found that spontaneous diabetic mice and wild-type normal mice have different skin tissue structure,in spontaneously diabetic mice skin sympathetic nerve specific symbol expression of tyrosine hydroxylase was significantly higher than that of normal mice,in normal mice tyrosine hydroxylase expression after the formation of the wound first increased rapidly and then back to nomal lever,tyrosine hydroxylase increased delay in healing process of diabetic mice.Increased expression of tyrosine hydroxylase,increased catecholamines,prolong the time of inflammation in diabetic mice,resulting in slow down the whole process of the wound healing.Studies have indicated that trauma and stress lead to elevated levels of catecholamine in blood and tissues,while high levels of catecholamine inhibit wound healing.As a non selective beta blocker,propranolol is first for treatment of cardiovascular diseases,with the role of antagonistic sympathetic nerve activity and catecholamine.Of pediatric burn patients during hospitalization be propranolol treatment can reduce hypermetabolism and reversal of muscle protein catabolism,promote healing of burn wounds.This study on the basis of the preliminary work,using propranolol treatment of normal mice and the spontaneous diabetic mice,inhibit sympathetic nerve activity,making wound model,mice were observed for wound healing,focuses on the detection of spontaneous diabetic mouse propranolol treatment after wound healing,compare the effects of beta adrenergic receptor blockers on the healing of skin wounds in diabetic mice.Mathods1.20 female C57BL/6J mice were randomly divided into propranolol group and control group,10 mice each.Propranolol group were given 50 mg propranolol dissolved in 100 ml of water to drink,the control group with normal water to drink.After sustained drug delivery for a week,a full-thickness excisional lesion were performed on mice back.Propranolol administration continue after the wound..1,3,5,7,10 days after the wound,pictures were taking by a digital camera,to observe the wound healing,measuring the wound area,wound healing rate was calculated.HE staining was used to observe the histological changes,inflammatory reaction,granulation growth and neovascularization of the wound,and the histological scores were compared.2.18 female Diabetic mice,were randomly divided into propranolol group and control group,9 mice each.a full-thickness excisional lesion were performed on the spontaneous diabetic mice back.Propranolol group and the control group,the wounds were external smear propranolol cream and cream base(except without propranolol,cream base components and propranolol cream ingredients exactly).2,5,7,10,14,17 days after the formation of the wound,changed dressing and randomly selected one diabetic mice for tissue cutting,when dressing propranolol group and the control group reapply containing or not containing propranolol cream and photographed.Measured the wound area and calculated the wound healing rate and 21 days when the remaining 3 diabetic mice were all killed.HE staining,Masson staining,toluidine blue staining were observed in wound reepithelialization,collagen fiber and mast cell situation;proliferating cell nuclear antigen(PCNA),CD68 immunohistochemistry based view cell proliferation and macrophage infiltration.Detection of Western blot in wound tissue PCNA and interleukin-1 beta(IL-1?)and angiopoietin 2(Ang2)expression,MMP-9.Results1.After the formation of wound on normal mice,1d,3d,5d,7dwound healing rate,propranolol group were higher than control group,compared with in 3D,5D,p<0.05 have obvious difference,and 1D,7d,p>0.05;10d two group wounds were completely healed.Wound with hematoxylin and eosin(he)staining visible and histological scores were found in the propranolol group early wound again epithelialization and granulation tissue growth were higher than those in the control group,and angiogenesis without significant difference.2.After the formation of the wounds on diabetic mice,2d,5d,7d,10 d,14d,17 d wound healing rate and propranolol group were higher than control group and P < 0.05.The 21 days after the formation of the wound,propranolol group had healed,not completely healed in control group,P > 0.05.HE staining,propranolol group again epithelial speed significantly faster than that of the control group,early stage inflammatory infiltrate obviously,weak in the later period.Masson staining showed that the expression of collagen arrangement of collagen level difference is not obvious in two groups.Toluidine blue staining,mast cells in wound tissue in the two groups were less.PCNA immunohistochemistry results showed that propranolol group early keratinocyte proliferation was significantly increased.CD68 showed that propranolol group of wound tissue in early infiltration of macrophage expression and expression of late is not obvious;control group,the wound tissue early expression of macrophages is not obvious and the late obvious expression.Western blot results showed that the IL-1,Ang2 expression of propranolol group was significantly lower than that of control group,(P < 0.05).2d propranolol group PCNA expression was higher than that of the control group,propranolol group MMP-9 expression in 2d,5d,7d,10 d were higher than those in the control group.Conclusion1.Propranolol can accelerate wound re-epithelialization and promote wound healing in normal mice.2.Propranolol significantly promote wound healing in spontaneously diabetic mice,the mechanism is stable which can obviously promote the re epithelialization,reduce inflammation and neovascularization.3.Topical propranolol may be a new method for treatment of diabetic ulcers,worthy of further study. |
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