| IntroductionThe skin contusion is a common injury in practice of forensic medicine ex-pertization, therefore, the estimation of skin contusion age became focus for domestic and international legal medical expert in the last few years.In the past, the skin contusion age was estimated by the color changes of the contusioned skin, but it is not of accuracy due to different color of human race, age and individual, etc. Afterwards, the skin contusion age can only be rough estimated because of the age is mutuall by counting the quantity of inflammatory cells. So the accurate method should be looking for. Along with the development for molecular phathology in medical science field, the changes of biological substance after trauma is more and more valued, and the new method for legal medical expert is provided.NFKB ( nuclear factor kappa B) transcription factor regulate encoding genes of various cytokines such as growth factors and adhesion molecules. Recently, studies have revealed NFKB is relationed to trauma. In this study, the expression of NFKB P65 and IKBa (inhibitory kappa B alpha, IKBa) in poly-morphonnucleared cells, mononuclear cells and fibroblastic cells during rat skin contusion repair will be investigated using immunohistochemical technique and the relationship with contusion will be revealed, which can provide the theorical evidence to identify the contusion age.Materials and Methods1 . Establishment of animal model of skin contusion and grouping A total of 33 health adult female and male Sprague - Dawley rats, each weight 160g -200g, were used. Skin contusion located in quadriceps muscle of thigh of posterior limb was made with falling of a 250g hammer from 150 centimeter high. 1. 5cm 1. 5cm square were taken from the contusioned sites after the animal were sacrificed by cervical dislocation at Oh, 3h, 6h, 9h, 12h, Id, 3d, 5d, 7d, 10d (3 rats in each group) postcontusion. The remaing 3 rats were used as control.2. Experiment methodThe immunostaining procedure followed the SABC technique, as follows: Tissue sections were deparaffinised and endogenous peroxidase activity was inhibitioned by 3% hydrogen peroxide aqueous solution for 20 min. antigen retrieval was then performed with heating in a microwave oven for 3 x5min.After serum incubated, sections were incubated with polyclonal antibodies against NFxB P65 (1:200) and lKBa(1:200) at 4C overnight. Goat anti -rabbit IgG - biotiny was incubated at 25 C for 20 minutes. The slides were incubated with SABC at 25 C for 20 minutes. Visualization of antibody binding was the DAB method. Finally, the sections were conterstained with hematoxy-lin, dehydrated and coverslipped.3. Statical analysisThe data was analysised by SPSS for Windows 11.0 with a significant level of P<0.01.Results1 . The expression of NF B P65 and I E in skin contusion repair In the control specimens, The positive staining of NF B P65 and I Ba were in the basal cell layer , spinous layer , granular layer and sweat epithelium , sebaceous gland epithelium. On postcontusion hour 3 , weak expression of NF BP65 and IKBa was detected in cytoplasma of polymorphonuclear cells ( PMNs) that infiltrated in the injured area, on postcontusion hour 6 to 12, the expression of NFB P65 and IicEa was prominently increased, on postcontusion hour 24, almost all of the mononuclear cells ( MNCs ) and PMNs were NFicB P65 positive and the cytoplasm and nucleus were all NFi |
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