Exercise Training in Rats Impairs the Replenishment of White Adipose Tissue after Partial Lipectomy

The aim of this study was to evaluate the effect of exercise training on the metabolism of rats following the partial removal of fat pads. Three-month-old male Wistar rats were subjected to the partial removal (L) of retroperitoneal white adipose tissue (RET) and epididymal white adipose tissue (EPI), or a sham operation (Sh). Seven days after surgery, both sets of rats were subdivided into exercised (LE or ShE) (swimming 90 min/day, 5 days/week, 6 weeks) and sedentary (LS or ShS) groups. Partial removal of the fat pads increased the lipogenesis rates in both the RET and EPI and decreased the weight and lypolysis rate of the EPI, while the RET weight was not significantly affected by lipectomy. In both lipectomized and sham-operated groups, exercise training caused a reduction in carcass lipid content, food intake, RET and EPI weights, and RET lipogenesis rate. On the other hand, the exercise training increased the percentage of diet-derived lipid accumulation in both tissues, either in sham and lipectomized rats. These results confirmed that regrowth is not uniform and depends on the particular fat pad that is excised. They also demonstrated that exercise training following the partial removal of fat pads modified adipose tissue metabolism, impaired the replenishment of adipose tissue, and decrease body adiposity.

Lipid Metabolism of Monosodium Glutamate Obese Rats after Partial Removal of Adipose Tissue

We analyzed the effects of partial fat pad removal on retroperitoneal and epididymal fat depots and carcass metabolism of control (C) and MSG-obese (M) rats. Three-month-old C and M male Wistar rats were submitted to either partial surgical excision of epididymal and retroperitoneal fat tissue (lipectomy, L) or sham surgery (S) and studied after 7 or 30 days. Retroperitoneal and epididymal tissue re-growth after lipectomy was not observed, as indicated by the low pads weight of the L groups. The lipolysis rate was stimulated in LC7 and LM7, probably due to surgical stress and low insulin levels. In LM7, but not in LC7, in vivo lipogenesis rate increased in retroperitoneal and epididymal fat tissue, as did the diet-derived lipid accumulation in epididymal fat tissue. Although these local increases were no longer present in LM30, this group showed a large increase in the percentage of small area adipocytes in both pads as well as increased carcass lipogenesis rate. The present data showed that the partial removal of fat depots affected the metabolism of control and MSG-obese rats differently. In the obese animals only, it stimulated both local and carcass lipogenesis rate as well as adipocyte differentiation, i.e. responses likely to favor excised tissue re-growth and/or compensatory growth of non-excised depots.