Effects Of Palmitate On IL-6 Secretion In Human Adipocytes And The Influences By Rosiglitazone

OBJECTIVE: To observe the effects of PA on IL-6 secretion and the influences of rosiglitazone(RSG) on them in cultured human adipocytes.METHODS: Omental and subcutaneous abdominal adipose tissue was obtained from 6 nondiabetic subjects and omental adipose tissue from 6 diabetic subjects undergoing selective surgery, and adipocytes were collected after collagenase treatment. For each culture, adipose tissue from only one subject was used. Viability of adipocytes was assessed by trypan blue exclusion and lactate dehydrogenase leakage. The isolated adipocytes were cultured with or without PA in the presence or absence of RSG. IL-6 released into the medium was measured by ELISA.RESULTS:1.The basal IL-6 concentration from omental adipocytes was higher than those in subcutaneous adipocytes at 6,12,24 hour in nondiabetic subjects. (p＜0.05).2.Omental adipocytes from nondiabetic patients were treated with different concentrations of PA (0.125 mmol/L, 0.25 mmol/L, 0.5mmol/L) for 24 hours, IL-6 secretion increased to 107%,154% and 202% of control levels(all p＜0.05).3.Exposed to high concentration PA(0.5mmol/L) for 24 hours ,the IL-6 secretion from omental adipocytes of nondiabetic patients increased significantly(202% of control levels). RSG reversed these changes, RSG 5umol/L leads IL-6 secretion decreased to 142% of control cells and 10umol/L to equal to control cells.(p＜0.05)4.The basal IL-6 levels from the omental adipocytes of diabetic patients were higher than in nondiabetic patients at 24 hour. (p＜0.05). 5. Treatment of omental adipocytes of diabetic patients with 0.5 mmol/L PA for 24 hours, IL-6 secretion increased ,and 10umol/L RSG i reversed the change. (p＜0.05).6. There was no statistical significant difference in the effects of PA and(or) RSG on IL-6 secretion from omental adipocytes between diabetic and nondiabetic patients.CONCLUSION:1. The basal IL-6 levels of omental adipocytes are higher than those of subcutaneous adipocytes in nondiabetic patients; and the basal IL-6 levels of the omental adipocytes of diabetic patients are higher than those in nondiabetic patients.2. In cultured omental adipocytes, PA promotes the secretion of IL-6 in a dose- dependent manner in nondiabetic patients, the promotion effect of PA was reversed by cotreatment with RSG.3. PA promotes the secretion of IL-6 and the promotion effect of PA is reversed by cotreatment with RSG in omental adipocytes of diabetic patients;.there was no difference of the promotes of PA on IL-6 secretion from omental adipocytes between diabetic patients and nondiabetic patients, so is the reverse by RSG.