Phosphatidylcholine induces apoptosis of 3T3-L1 adipocytes

The viability of 3T3-L1 pre-adipocytes and differentiated 3T3-L1 cells was measured after treatment of PPC alone, its vehicle sodium deoxycholate (SD), and a PPC formulation. Western blot analysis was performed to examine PPC-induced signaling pathways.PPC, SD, and PPC formulation significantly decreased 3T3-L1 cell viability in a concentration-dependent manner. PPC alone was not cytotoxic to CCD-25Sk human fibroblasts at concentrations <1 mg/ml, whereas SD and PPC formulation were cytotoxic. Western blot analysis demonstrated that PPC alone led to the phosphorylation of the stress signaling proteins, such as p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, and activated caspase-9, -8, -3 as well as cleavage of poly(ADP-ribose) polymerase. However, SD did not activate the apoptotic pathways. Instead, SD and PPC formulation induced cell membrane lysis, which may lead to necrosis of cells.PPC results in apoptosis of 3T3-L1 cells.Mesotherapy is a new technique of injecting drugs into the mesoderm for the treatment of local conditions [1]. This method allows the use of increased concentration of drugs and can produce greater treatment effects. Mesotherapy has been used for many infirmities, such as fat emboli, chronic pain, hyperlipidemia, and liver problems [2]. Phosphatidycholine (PPC) formulation has been widely-used to dissolve local fat deposits as a safe nonsurgical alternative to liposuction [3]. Many clinical studies have reported that the subcutaneous injection of PPC formulation reduces fat [3-5]. Although the biochemical mechanisms are very poorly studied, it has been suggested that no enzymatic lipolytic pathway is involved [6]. Thus, it is thought that the PPC formulation dissolves local fat deposits in a nonspecific manner [7]. PPC formulation has not been approved by the Food and Drug Administration (FDA) for use in lipodissolution.PPC is a lecithin-derived phospholipid [4], which is widely-distributed in human cell membranes [8]. The Lan