Study About The Secretion Of Leptin And Andiponectin By Human Omental Preadipocytes

Objective:The aim of this study is to investigate the rule of secretion of leptin and adiponectin during the process of cell differentiation when culturing human omental preadipocytes primarily in vitro.Methods:1.Omental adipose tissue were obtained from patients undergoing elective open-abdominal surgery(BMI＜25kg/m²,age40±8).None of the patients had diabetes or severe systemic illness.None was taking medications known to affect glycometabolism or lipid metabolism..2.Using collagenase -digesting method,human preadipocytes were separated from omental adipocyte tissue and identified by extracting stained intracytoplasmic lipid with oil red O. The morphological changes of the cultured cells were observed and the growth curve was drawn by MTT.And then we investigated the processes of proliferation and differentiation of human omental preadipocytes primarily in vitro.3.Collecting culture supernatants every 2 days during proliferation and differentiation,the contents of leptin and adiponectin were detected by enzyme linked immunosorbent assay (ELLSA).4.Statistical analysis.Values were given as means±SE.Differences were considered significant at a value of P＜0.05).Results:1.Human preadipocytes were primary cultured successfully.The cultured fibroblast-like cells were homogeneous and the day of 3^rd-10^thof its proliferate-phase was increased logarithmic phase.After preadipocytes being induced into differentiation phase,lipid droplets could be seen on the 4^thday and were increased with the differentiation process going on,Most preadipocytes became mature adipocytes about on the 21^stday.2.In proliferation:The low level of leptin could be detected in the collected culture supernatants of preadipocytes.Whereas the adiponectin could not be detected in the culture supernatants.3.In differentiation:The volume of leptin increased and arrived to peak on the 17^thday of differentiation.Then the secretion of leptin kept a high rate until the differentiation process was completed.The adiponectin could be detected in the culture supernatants on the 7^thday of differentiation,while the adipocytes contained lipid droplets could be observed under inverted microscope,The max secretion was detected on about the 17^thday.An obvious descent of the adiponectin level could be observed on the 21^stday(P＜0.05)when the lipid were not decreased.Conclusion:1.The primary culture method of human omental preadipocytes is established successfully in vitro.It provided a laboratory model for further investigation on central obesity and insulin resistant diseases.2.Leptin and adiponectin show different secretion-mode on the primary cultured human omental preadipocytes.Adiponectin may serve as a specific marker for preadipocyte differentiation.3.Adipocytes in different phase or state may have different function of secreting leptin and adiponectin.It provided a laboratory evidence for investigating the mechanism of the two adipocytokine' secretion-mode in obesity patients.That is,the secretion of more leptin and less adiponectin may be more associated with the size of preadipocytes than with the.number of preadipocytes.4.Adiponectin may have a feedback suppression function of autocrine/paracrine and its down-regulation mechanism may be more associated with the differentiation than the accumulation of lipid which provided a laboratory province in vitro.