The Adipogenic Differentiation Trend Of White And Brown Adipose-derived Mesenchymal Stem Cells In Rat

Background The mammals body contains two types of adipose tissue:white adipose tissue(WAT)and brown adipose tissue(BAT).The former is an energy storage organ,the latter is an energy-consuming organ.Both kinds of adipose tissue contain mesenchymal stem cells,whether the two mesenchymal stem cells have a difference in the process of differentiation to fat is still a problem.This is the focus of this article research.Objectives To compare the differences in the structure and composition between WAT in inguinal fold and BAT in interscapular area in rat,to discuss the differences of adipogenic differentiation characteristics between the white adipose-derived mesenchymal stem cells(WADMSCs)in inguinal fold and brown adipose-derived mesenchymalstem cells(BADMSCs)in interscapular area.Methods 1.WAT in inguinal fold and BAT in interscapular area were separated in vitro,the differences of morphological characteristics between the two types of adipose tissue were exeamined by HE staining of paraffin sections and transmission electron microscopy.2.Immunohistochemical staining was used to compare the differences between the two types of adipose tissue.3.WADMSCs in inguinal fold and BADMSCs in interscapular area were digested by collagenase type I,then filtrated and centrifugated,compare morphological differences between the two types of mesenchymal stem cells.Immunofluorescence technique was used to appraise two kinds of P3 mesenchymal stem cells.4.Immunohistochemistry and immunofluorescence techniques were used to test the adipogenic differentiation rate of each kind of mesenchymal stem cells,and to detect whether the cells were white fat cells or brown fat cells after adipogenic induction and differentiation.5.Both mesenchymal stem cells after DAPI staining were transplanted to the groin area.Sample tissues were obtained respectively in 1,2 and 3 weeks.Immunofluorescence technique was used to detect the differentiation trend of the implanted cells.Results 1.With gross observation,WAT in inguinal fold looks bright white,BAT in interscapular area looks brown.HE staining showed that WAT consists of big cavity type cells,BAT is mainly composed of small cavity type cells,along with the capillaries and big vacuoles type cells;Tem showed WAT has less organelles,BAT has rich of mitochondrias.2.Immunohistochemical showed WAT did not express UCP1,BAT expressed UCP1 in large quantities.3.Cell body of BADMSCs were shining brilliantlier than WADMSCs,and the former have more slender cells swelled.Two kinds of cells all expressed mesenchymal stem cell markers,CD73,CD90,CD105.4.Adipogenic differentiation of WADMSCs was 0.205±0.069,while Adipogenic differentiation of BADMSCs was 0.165±0.053.Adipogenic rates of the two kinds of mesenchymal stem cells have no statistical significance(P> 0.05).5.After adipogenic cells implanted in the body,brown adipose specific proteins UCP1 were expressed from two kinds of stem cells in 1,2 and 3 weeks' tissues.Conclusions The cell morphology and adipogenic rates of WADMSCs and BADMSCs showed no obvious difference.Both WADMSCs and BADMSCs cultured in vitro and in vivo were differentiated into brown fat cells after induction,this is great significance for using ADMSCs to guide the body metabolism.