Preliminary Study Of The Distribution And Characteristics Of Nerve Growth Factor In Pathological Scar

Objective:As the first discovered neuropeptide,Nerve growth factor (NGF) plays a very improtant role in nervous system diseases and reparative regeneration,and now people focus on the effcet of NGF in pathological scar. Studies had shown that NGF in hypertrophic scars had strong expression, but NGF density in keloid and atrophic scars and where distributed NGF in abnormal scars were not been reported. This experiment is to investigate the distribution of the NGF in Pathology scar and the porential mechanism through the immunohistochemisty assy of the NGF in Pathology scar. Methods:To collect 36 clinical scar excision specimens after surgery, then divided them into three groups:A keloid, B hypertrophic scar, C atrophic scar, another 12 cases of the normal skin samples were used as control group. The specimens were fixed by 10% neutral formalin for 12h, the conventional gradient alcohol was used to dehydrate it and the paraffin was used to embed the sections, respectively on the hematoxylineosin(HE) staining and immunohistochemistry.In immunohistochemistry positive signal of NGF was the brown granules. NGF image analysis method:①NGF positive particles of each group were observed and count under the 400 times microscope in the layer of epidermis and dermis. Each slice were observed five horizons whichever is compared with the numbers.②Using Image-Pro Plus 6.0 image analysis system, the IOD was used to stand for expression of NGF, said intensity value with the epidermis and dermis of each section depicting the five horizons, each horizon were measured IOD values, and the a mean of the samples IOD values of the epidermis and dermis were compared. Result:1 HE staining under light microscope morphology:①Normal skin epidermis and the cuticle were relatively thick than transparent layer; dermal papilla prominent had obviously larger number of papillae; see reticular layer adhesion of fibroblasts, nuclear was small, colo was depth, less cytoplasm and fewer.②Keloid epidermis atrophy, basal layer, spinous layer cell body large number of layers increased; in granular layer, transparent layer and the stratum corneum we could only see a thin layer of eosinophilic staining whith could not been distinguished; the dermal papilla could be seen, milk the small number of sudden, low and flat; net woven thick, dense, see the thick collagen, stained dark, disordered, glass-like degeneration, and visible blood vessels, lymphatic vessels, capillary closure; two layers of fibroblasts were seen, the number was more.③Hypertrophic scar group basal layer and spinous layer cells were relatively higher and its inter-connected than normal skin cells became loose; a transparent layer and stratum corneum thinning significantly; dermal papilla prominent degree than normal skin and low, flattened, the number of less than normal skin; reticular layer thicker, more dense, and visible blood vessels, lymphatic vessels, telangiectasia; two layers of fibroblasts were seen, the number was more.④Atrophic scar low columnar epidermal basal cells and dermal were connected, attached to the basement membrane, the relative number of layers was relatively small scar; their cells was loose connection than normal skin.Granular layer of spindle cells were more flat, significantly thinner than normal skin; Transparent layer and stratum corneum became thinning significanly.Dermal papilla layer was loose, light staining, which under this layer was reticular layer, compared with hypertrophic scar and keloid thin, which was more compact, thick collagen, stained dark, more irregular, and showed that capillary closure. 2 NGF immunohistochemical staining image analysis:(1)The scar-positive particles in epidermis NGF, NGF average optical density and integral optical density was significantly higher than the normal skin group, which was statistically significant (P<0.01).Atrophic scar-positive particles in epidermis NGF, NGF average optical density and integral optical density was less than that of keloid and hypertrophic scar group, which was statistically significant (P<0.01).Keloid skin NGF group average optical density and integral optical density of NGF and hypertrophic scar group was not statistically significant (P> 0.05).(2) The group of dermal scar positive particles NGF, NGF average optical density and integral optical density was significantly higher than the normal skin group,which was statistically significant (P<0.01).Atrophic dermal scars NGF positive particles, NGF average optical density and integral optical density was significantly lower than the keloid and hypertrophic scar group, which was statistically significant (P<0.01).Keloid dermal NGF group average optical density and integral optical density of NGF and hypertrophic scar group was not statistically significant (P> 0.05). Conclusion:1 The stained brown particulate matter NGF presented in the normal skin and scar epidermis and dermis layers, the number of positive granules in epidermis expressed more.2 NGF-positive granules in the scars were widely distributed, whic were high density, concentrated color The epidermis had a lot of NGF-positive, dense dermal fibroblasts had more,Keloid scar epidermis and epidermal NGF group had the largest number of positive particles.3 NGF-positive atrophic scars than fine particles less keloid and hypertrophic scars, keloid and hypertrophic scar group of NGF-positive group was no statistical difference between the particles.