Taurine supplementation regulates Iκ-Bα protein expression in adipose tissue and serum IL-4 and TNF-α concentrations in MSG obesity

Obesity is usually associated with low-grade inflammation, which impairs insulin action. The amino acid, taurine (TAU), regulates glucose homeostasis and lipid metabolism and presents anti-inflammatory actions. Here, we evaluated whether inflammatory markers are altered in the serum and retroperitoneal adipose tissue of monosodium glutamate (MSG) obese rats, supplemented or not with TAU. Male Wistar rats received subcutaneous injections of MSG (4 mg/kg body weight/day, MSG group) or hypertonic saline (CTL) during the first 5 days of life. From 21 to 120 days of age, half of each of the MSG and CTL groups received 2.5 % TAU in their drinking water (CTAU and MTAU). At 120 days of age, MSG rats were obese and hyperinsulinemic. TAU supplementation reduced fat deposition without affecting insulinemia in MTAU rats. MSG rats presented increased pI kappa-B alpha/I kappa-B alpha protein expression in the retroperitoneal adipose tissue. TAU supplementation decreased the ratio of pI kappa-B alpha/I kappa-B alpha protein, possibly contributing to the increased I kappa-B alpha content in MTAU adipose tissue. Furthermore, MSG obesity or supplementation did not alter TNF-alpha, IL-1 beta or IL-6 content in adipose tissue. In contrast, MSG rats presented lower serum TNF-alpha, IL-4 and IL-10 concentrations, and these alterations were prevented by TAU treatment. MSG obesity in rats was not associated with alterations in pro-inflammatory markers in retroperitoneal fat stores; however, reductions in the serum concentrations of anti-inflammatory cytokines and of TNF-alpha were observed. TAU treatment decreased adiposity, and this effect was associated with the normalization of circulating TNF-alpha and IL-4 concentrations in MTAU rats.