Experimental Study Of Deferoxamine And Argatroban Lessening Toxic Effects Of Non-compressive Hematoma On Expanded Skin Flap

Background and Objective:Skin soft tissue expansion,which was a conventional therapy for reparation of tissue defect and organ reconstruction in plastic surgery,had been used in clinic generally.But some complications,such as: hematoma,infection,skin flap necrosis and etc,appeared after skin soft tissue expansion.Hematoma was the most frequent complication.Hematoma could not only make skin flap ischemic,but have toxic effects on skin flap.Moreover,hematoma was related to infection and skin flap necrosis closely.At present,removing the sludged blood was the only method to treat hematoma formed after skin soft tissue expansion.There was no potent medicine to release the skin flap's impairment.The objective of our research were exploring the mechanisms which the hematoma causes the skin flap's impairment,and seeking the medicines which can lessen the effect on the skin flap's impairment and exploring the medicines' mechanism of action.PartⅠThe study of deferoxamine lessening the toxic effects of iron in non-compressive hematoma on pre-expanding skin flapMethods:Thirteen 4～8-month-aged white minipigs were selected.10 operation zones were designed on two side of vertebral column in each minipig.The total operation zones were 128.128 kidney-shaped expanders were implanted.128 pre-expanding skin flaps were formed.The skin flaps were divided into control group, hematoma group,deferoxamine group and argatroban group randomly.The content about argatroban group would describe in PartⅡ.The control group:there was no other treatment after expander implantation.The hematoma group:15ml blood was infused into the dissected capsules after expander implantation.The deferoxamine group:15ml blood and 270mg deferoxamine were infused into the dissection capsules after expander implantation.Seperately,pieces of skin flap tissue were taken from the pre-expanding skin flaps 24h,72h,120h after soft tissue expansion.8 days after the operation,normal sodium was injected into the 8 remained expanders.Two months later,Pieces of tissue were taken from the expanded skin flap.The blood flow of pre-expanding skin flaps were detected 2h after the operation.The contents of iron and malonaldehyde(MDA),the activity of myeloperoxidase(MPO),the thickness and collagen content of the expanded skin flap's capsule,immediate contraction rate of expanded skin flap were detected.Results:(1) The blood flow of pre-expanding skin flaps which were detected 2h after the operation had no significant difference among the three groups(P＞0.05). (2)Compared with the control group,the contents of iron and MDA and the activity of MPO in hematoma group increased(P＜0.01).Compared with the hematoma group, the contents of iron and MDA in deferoxamine group decreased(P＜0.01).The activity of MPO had no significant difference between hematoma group and deferoxamine group(P＞0.05).(3) Compared with the control group,the thickness and collagen content of the expanded skin flap's capsule and immediate contraction rate of expanded skin flap in hematoma group increased(P＜0.01).The thickness and collagen content of the expanded skin flap's capsule and immediate contraction rate of expanded had no significant difference between hematoma group and deferoxamine group(P＞0.05).PartⅡStudy of argatroban lessening the effects of thrombin in noncompressive hematoma on expanded skin flap and the mechanismsExperimentⅠStudy of thrombin on proliferation of fibroblasts isolated from mini pig's skinMethods:The minipig skin fibroblasts were cultured in monolayer.The vigor of fibroblasts which were stimulated by different concentration of thrombin was detected by MTT.The contents of hydroxyproline in supernatant were detected by chloramines T method.The expressions ofα-SMA in fibroblasts which were stimulated by thrombin,were detected by immunohistochemistry staining.After argatroban was infused into the culture solution,the detections mentioned above were repeated. Results:(1) The cells appeared to be the typical fibroblast,the immunohistochemistry staining ofα-SMA in the cells were positive.(2) Compared with the group without thrombin,the OD value of the groups contained different concentration of thrombin were increased(P＜0.01),the OD value of the groups contained different concentration of thrombin and argatroban had no changes(P＞0.05).(3) Compared with the group without thrombin,the hydroxyproline content in supematant of the groups contained different concentration of thrombin were increased(P＜0.01),the hydroxyproline content in supernatant of the groups contained different concentration of thrombin and argatroban had no changes(P＞0.05).(4)α-SMA expressed in the fibroblast stimulated by thrombin.The expression ofα-SMA was inhibited by argatroban.ExperimentⅡStudy of argatroban lessening the effects of thrombin in noncompressive hematoma on expanded skin flapMethods:This experiment had three groups:control group,hematoma group, argatroban group.The dsigns of control group and hematoma group were same to the first part.The argatroban group:15ml and 500μg argatroban blood were infused into dissected capsule after expander implantation.Seperately,pieces of skin flap tissue were taken from the pre-expanding skin flaps 24h,72h,120h after soft tissue expansion.8 days after the operation,normal sodium was injected into the 8 remained expanders.Two months later,Pieces of tissue were taken from the expanded skin flap. The contents of MDA,the activity of MPO,the thickness and collagen content of the expanded skin flap's capsule,immediate contraction rate of expanded skin flap were detected.The expression of ICAM-1 in pre-expanding skin flaps andα-SMA in expanded skin flaps were detected by immunohistochemistry staining.Results:(1)Compared with control group,the activy of MPO and expression of ICAM-1 in hematoma group increased(P＜0.01).Compared with hematoma group, the activy of MPO and expression of ICAM-1 in argatroban group decreased(P＜0.01).(2) Compared with control group,the content of MDA in hematoma group 72h and 120h after operation increased(P＜0.01).Compared with hematoma group,the content of MDA in argatroban group 72h and 120h after operation decreased(P＜0.01).(3) Compared with control group,the thickness and collagen content of the expanded skin flap's capsule,immediate contraction rate of expanded skin flap,the expression ofα-SMA in hematoma group increased(P＜0.01).Compared with hematoma group,these indexes in argatroban group decreased(P＜0.01).Conclusions1.The hematoma which formed after skin soft tissue expansion can strengthen the lipid peroxidation and inflammatory reaction in the skin flap.Using deferoxamine locally can reduce the lipid peroxidation caused by hematoma.This role of deferoxamine results from decreasing the content of iron in the skin flap.Using argatroban locally can reduce the lipid peroxidation and inflammatory reaction caused by hematoma.This role of argatroban results from inhibiting thrombin in hematoma.2.Thrombin can induce fibroblast's proliferation,make fibroblast product more collagen,increase the expression ofα-SMA in fibroblast,transform fibroblast to myofibroblast.Argatroban can inhibit these effects of thrombin.3.Hematoma can make the capsular thickness thicken,increase collagen content of the capsule and immediate contraction rate of expanded skin flap.Using deferoxamine locally can not lessen these effects of hematoma.Using argatroban locally can lessen these effects of hematoma.This role of argatroban is result from inhibiting thrombin in hematoma.