Anti-Obesity and Metabolic Effects of Forskolin in Obese C57BL/6J Mice

Forskolin (FSK) induces the browning of white adipose tissue (WAT) through the activation of adenylate cyclase (AC) and cyclic adenosine monophosphate (cAMP) generation. When administered intravenously or orally, FSK undergoes significant metabolism and accumulation in the liver and other tissues, resulting in high side effects and low anti-obesity effects due to trivial amounts reaching WAT. This study examines the potential anti-obesity and metabolic effects of the inguinal WAT (IWAT) delivery of FSK in high-fat diet-induced C57BL/6J obese mice. Mice received one of the following treatments twice weekly for 4 weeks: 1. Control into both IWAT depots (Con^both); 2. FSK 15 mg/kg body weight (BW)/injection into both inguinal WAT (IWAT) depots (FSK15^both); 3. FSK 7.5 mg/kg BW/injection into both IWAT depots (FSK7.5^both); and 4. FSK 7.5 mg/kg BW/injection into the left IWAT depot (FSK7.5^left). Both the FSK15^both and FSK7.5^both treatments improved metabolic parameters by lowering blood glucose, enhancing glucose tolerance, and reducing serum insulin and cholesterol. The FSK15^both treatment had a greater impact on IWAT, resulting in smaller adipocytes and increased expression of Ucp1 and Tmem26 mRNA levels. All FSK treatments also reduced inflammatory and lipogenic markers in the liver, indicating improved hepatic metabolism. These findings suggest that local delivery of FSK into subcutaneous WAT is a potential strategy for combating obesity and improving metabolic health. However, further studies are needed to confirm the statistical and biological significance of these effects.