The Improvement Of Photoaging Skin Texture On Nude Mouse By Nanofat Graftint

Objection:Nanofat was injected into photoaging nude mice subcutaneous induced by ultraviolet irradiation and the changes of dermis thickness,microvessel density and cell proliferation was evaluated.Nanofat was periodically taken out to observe its absorption condition.To preliminarily discuss the mechanism of nanofat improving photoaging nude mice skin texture and to provide related objective evidence for the clinical application of nanofat on photoaging skin.Methods:1.Nude mouse were irradiated by UVB with a certain distance from the back of the skin,MED was explored.Then nude mice were divided into 2 groups,control group and UVB group.UVB group were irradiated for 8 weeks,6 times a week.HE and Masson staining were performed to observe skin structure,dermis thickness.2.With side hole aperture of 5mm liposuction needle,macrofat was suction.And with 1mm side hole aperture of 1mm liposuction needle,microfat was suction.While nanofat was mechanically emulsificated.Three kinds of fat were compared by eyes,and Calcein-AM fluorescent staining distinguish difference.Then nanofat was digested by collagenase and cultured.3.Twenty-seven 6 to 8 weeks female BALB/c nude mice were included and divided into four groups:Nature group(no intervention),PBS group(ultraviolet irradiation+PBS injection),ADSCs group(ultraviolet irradiation+ADSCs injection,),Nanofat group(ultraviolet irradiation+nanofat injection).Four weeks after injection,skin specimens were collected:the skin texture of each group were evaluated by general observation;HE and Masson staining were performed to observe skin structure,dermis thickness and collagen fibers arrangement;immunohistochemistry stain of CD31 and Ki67 were performed to observe the microvessel density and cell proliferation respectively;Anti-human nuclei stain was performed to detect whether human derived cells persisted in skin;Elisa was made to detect the grocth factors on skin regeneration.Another Nanofat injection group,collection specimens were performed respectively after 2,4,6 and 8 weeks to follow up the absorption condition of nanofat.Result:1.The minimal erythema dose was 160mJ/cm~2.After 2 weeks ultraviolet irradiation,some nude mice dorsum skin began to desquamate.After 8 weeks ultraviolet irradiation,almost all the nude mice skin became pachylosis with increasing microgroove.Masson staining showed that the mean dermis thickness decreased after ultravio-let irradiation.2.Under microscope observation,most adipose cells structures were destroyed leaving local sporadic integral adipose cells.After culturing,naofat was found ADSCs prolifing.3、Four weeks after injection of nanofat,in terms of skin general observation:Nanofat group and ADSCs group showed no obvious difference compared with PBS group.In terms of dermis thickness:ADSCs group and Nanofat group showed obvious thicker dermis than PBS group(P<0.05)and ADSCs group showed thicker dermis than Nanofat group.In terms of dermis microvessel density:ADSCs group and Nanofat group showed higher microvessel density than PBS group(P<0.05),there was no difference between ADSCs group and Nanofat group.In terms of cells proliferation:ADSCs and Nanofat groups showed significant different than PBS group(P<0.05),and ADSCs group showed more increased epidermic cells proliferation than Nanofat group(P<0.05),all groups showed no differ-rence of dermis cells proliferation.Nanofat contained many kinds of growth factors related to skin regeneration,such as VEGF,EGF,bFGF,TGF-β,IGF,IL-6 and so on.Follow up of nanofat absorption showed:nanofat was absor-bed gradually after injected subcutaneous nanofat were absorbed and 8 weeks after njection,almost all the subcutaneous nanofat were absorbed.Conclusion:The adipose cells structures of nanofat were destroyed,but it contains ADSCs and many kinds of growth factors related to skin regeneration.Nano fat have the ability to improve dermis thickness,microvessel density multiplication and epidermic cells proliferation.Almost all the nanofat was absorbed gradually in photoaging nude mice subcutaneous 8 weeks after injection.