| ObjectiveSkin wound healing is a complex and continuous process,concluding clotting of blood components,inflammation,granulation tissue formation,re-epithelialization, connective tissue retraction and fibroplasia.Oncogene c-jun is a member of immediately early genes(IEGs) jun family,and belongs to nuclear transcription factor of basic leucine zipper(bZIP) family.Combined with many gene promotors,c-jun is involved in the regulation of gene transcription,and its products play a crucial role in gene expression,cell proliferation,differentiation and apoptosis.In this study,the level of c-jun in incised skin wound was detected by immunohistochemical technique and Western blot.The investigation is targeted at exploring the possible function of c-jun in skin wound healing and its applicability to the wound age estimation.Materials and MethodsA total of 55 adult,healthy mice of either sex,each weighting 35～40g,were divided into eleven groups randomly,one control group and ten skin incision groups.A 1.5cm-long full-thickness incision deep to the fascia was made with a scalpel in the skin layer on the central dorsum of each mouse under sterile technique after the mouse was anesthetized by inhalating diethyl ether.After injury,each mouse was housed individually and fed with sterilized food and distilled water to prevent from infection. The 1.5cm×1.0cm specimens were taken from the wounded site after the mice were executed by cervical dislocation at Oh,3h,6h,12h,1d,3d,5d,7d,10d and 14d post-injury to prepare for the subsequent procedures.The level of c-jun in mouse skin incised wound was detected by immunohistochemical staining and Western blot,and the non-incised mouse skin was used as control.The number and ratio of c-jun-positive cells were counted and analyzed by microscope.The band integral optical density value was analyzed by software of Fluochem V2.0.The data were analyzed comparatively by the software of SPSS13.0 for Windows. ResultsA weak immunoreactivity of c-jun was detected in epidermis,hair follicle,and sebaceous gland in normal mouse skin.Expression of c-jun was detectable in polymorphonuclear cells(PMNs) in the wound specimens aged in 3h.In the wound specimens aged from 6h to 24h after injury,c-jun-positive immunoreactivity was identified in a large number of infiltrating PMNs and part of mononuclear cells (MNCs).Afterwards from 1d to 3d post-wounding,the c-jun-positive cells were mainly found of MNCs and spindle-shaped fibroblastic cells(FBCs) and mainly in FBCs from 5d to 14d post-injury.Morphometrically,the ratios of the number of c-jun-stained PMNs,MNCs and FBCs to total number of the cells in the wounds were evaluated and calculated.The ratio of the c-jun-positive cells was low in the wounded specimens aged in Oh,and elevated in the wound specimens aged 3h and kept a highly level from 1d to 5d post-injury,with a peak at 12h.Thereafter,the ratios decreased from 7d to 14d and minimized in the specimens aged 14d,with the second peak at the 7d.There were significant differences in ratios of c-jun-positive cells between the neighboring time groups(P＜0.05) except that at 3d post-injury.The obvious bands of 40kD were noticed at 12h and 7d and the expression of c-jun revealed a time-dependent pattern.Conclusions1.The expression of c-jun was detected in epidermis,hair follicle and sebaceous gland of normal mouse skin.2.The expression of c-jun was detected in PMNs,MNCs and FBCs during the incised skin wound healing in mice.3.The results suggested that c-jun may play an important role in inducing the apoptosis of PMNs,MNCs and FBCs during the incised skin wound healing in mice.4.The expressional time-dependent pattern of c-jun may be used as a marker for the wound age determination of the incised skin.
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