Adipocytes Affect Function And Accumulation Of Macrophages In Adipose Tissue Of Intrauterine Growth Retardation Rats With Catch-up Growth

Objective To investigate macrophages accumulate in the adipose tissue andincrease the secretion of proinflammatory cytokines IL-6and TNF-α, expressing ofNFκB, JNK signaling pathways in rats with intrauterine growth retardation (IUGR),in order to explore the relationship between adipose tissue inflammation and insulinresistance in rats with IUGR-CG.Methods Female Sprague-Dawley (SD) rats of clean grade were divided intotwo groups randomly: food-restrict group and control group. Once pregnant, rats offood-restrict group were fed with only30%food of control group everyday tillparturition to establish IUGR animal model, and the newborns were fed with morebreast milk to achieve their catch-up growth. Adipose tissue derived fromepididymal fat pad, perirenal of8weeks old rats was immunohistochemical stainedafter being made of paraffin sections. Primary cultured rat abdominal macrophageswere co-cultured with primary cultured adipocytes for24hours in transwell inserts.The levels of IL-6and TNF-α in the supernatant of co-cultured cells were detectedby the way of ELISA. The expressing levels of NFκB and JNK signaling pathwaysin co-cultured macrophages were detected by Real-time PCR and Western blot. Thespecific marker of macrophages F4/80was determined by immuneohistochemical tojudge the accumulation of macrophages in adipose tissue of IUGR-CG.Results The weight, length and body mass index(BMI) of newborns and1weeks old IUGR rats were significantly less than the controls(p<0.01), but at2weeks old,IUGR rats accomplished catch-up growth and the development parameters can beobserved exchanged in the two groups (p<0.01). The yellow-brown precipitates inthe adipose stromal of8weeks old IUGR-CG rats in immunohistochemical paraffinsections were more than the controls. The levels of IL-6and TNF-α in thesupernatant of primary co-cultured cells of IUGR-CG rats were higher comparedwith the controls (both p<0.01). The relative expressing levels of NFκB and JNKmRNA in primary co-cultured macrophages of IUGR-CG rats were higher than thecontrol group (both p<0.01), and the corresponding protein levels were higher in theIUGR-CG group (p<0.01and p<0.05).Conclusion Adipose tissue of IUGR-CG rats exist chronic inflammation andmacrophages accumulate in it. Adipocytes and macrophages both have effect on theexpressing levels of proinflammatoty cytokines IL-6, TNF-α and NFκB, JNKsignaling pathways, which promote the progress of insulin resistance.