Age Induces Female Facial Lipoatropy And Decreases Adipose-derived Stem Cells Proliferation And Differentiation

Subcutaneous adipose tissue(SAT) is located between the dermis layer and the fascia,stored in the subcutaneous adipose tissue. SAT, visceral adipose tissue(VAT) in the abdominal cavity and yellow adipose tissue in bone marrow constitute the body's adipose tissue. About two-thirds of the body fat is SAT. With the increasing of the aging process,human SAT become less gradually. Owing to the structural changes of the elastic fibers and collagen fibers the skin elasticity and tension is weak All these changes result in the elderly skin sagging and wrinkles. It is a significant facial collapse phenomenon of the serious facial SAT atrophy in the human aging process. In previous research, facial decrepitude research mainly focused on superficial phenomenon and organization structure changes, but the mechanism of facial SAT is little studied.In order to further understand the aging effects on female face and the development of anti-aging drugs, it is necessary to be understood the regulation mechanism of female facial SAT atrophy, proliferation and differentiation of adipose-derived stem cells(ADSCs) during aging. The main results of this study are as follows:1. The female facial SAT from different ages were paraffin section, then Hematoxylin and Eeosin(H&E) staining. We found that the cell size of young group is greater than the old group at the same magnification; The young group's cells population was significantly less than old group(P<0.01) at 200 times magnification. The results show that female facial subcutaneous adipocyte become smaller during aging.2. To confirm of lipolysis ability during aging process, we test the related genes(PERILIPIN, ATGL, HSL) of lipid droplets hydrolysis expression in female facial SAT. By qRT-PCR, the mRNA level of PERILIPIN, ATGL in young group was significantly higher than the old group(P<0.001); but the HSL mRNA has a declining trend in the old group,but not significant(P=0.4238); And Western Blot also found that the expression of PERILIPIN and ATGL protein in the young group were significantly higher than the old group(P<0.05). qRT-PCR and Western Blot results show that aging leads to lipolysis decreased in female facial SAT.3. The mitochondria regulatory factors(PGC-1?, COXIV) are different expression in female facial SAT during age. In the old group, qRT-PCR results showed that the mRNA of PGC-1? and COXIV were significantly decreased(P<0.05). The protein level expression of PGC-1? was also detected and significantly lower in the old group(P<0.05). The results show that the female facial SAT mitochondrial metabolism decrease with aging.4. The ADSCs could be harvested from different female facial SAT, and detecting ADSCs proliferation ability by EdU test. Experiment results show that the young group's cell population significantly more than old groups' in growth phase(P<0.05). So that Aging reduces human ADSCs' proliferation.5. The cells were dyed with oil red O to observed the content of lipid after adipogenic differentiation. Lipid droplets could not be observed after 2d after differentiation. After 5d adipogenic differentiation, lipid droplets can be observed in two groups and the young group is significantly higher than the olds(P<0.05). After adipogenic differentiation 8d, 10 d,it is still remain significant higher in the young group(P<0.05). We could conclude that aging reduces human ADSCs' adipogenic differentiation ability.6. In order to detect human ADSCs differentiation mechanism from different age, we detected that the mRNA expression of adipocyte differentiation regulatory genes(PPARG,LPL, AP2, ADIPOQ) by qRT-PCR technology after 0d, 2d, 5d, 8d, 10 d adipogenic differentiation. The results showed the mRNA expression of PPARG, LPL, AP2, ADIPOQ have significantly increased in the early stage(P<0.01) after adipogenic differentiation; but PPARG and LPL mRNA expression was a slight decline in the late differentiation stage. At the same stage of differentiation, the mRNA of PPARG, LPL, AP2, ADIPOQ in the young group were significantly higher than the old group's(P<0.05 or P<0.01); with the increasing of differentiation days, the two groups' differences is gradually decreased, and finally the mRNA expression levels of LPL, ADIPOQ have no differences in the final stage.The results showed that the mRNA expression of adipocyte differentiation regulatory genes(PPARG, LPL, AP2, ADIPOQ) were decreases during aging lead to reduction of the adipogenic differentiation ability.