王浆主蛋白（MRJPs）对张氏肝细胞的促增殖作用及其机制
摘要
Major royal jelly proteins (MRJPs) are the soluble proteins in royal jelly, which account for 82%-90% of total royal jelly proteins. MRJPs are consisted of ten members, i. e. MRJP1-MRJP9 and MRJPψ, whose biological functions include enhancing cell proliferation, inducing differentiation, modulating immune responses, accelerating wound healing, etc. MRJP1 with 57 ku in molecular mass was found possessing proliferation-promoting activities, enhancing proliferation of primary cultured rat hepatocytes and increasing albumin production in the absence of serum. MRJPs could significantly stimulate the proliferation and growth of endothelial progenitor cells (EPC). The recombinant MRJP1 could significantly stimulate growth of Tn-5B-4 cell from Trichoplusia ni, and affect cell shape and adhesion to the substrate. Similar activities were also found in normal human neonatal skin fibroblasts NB1 RGB cell, MC3T3-E1 cell and Jurkat cell, etc. All these findings showed the potential of MRJPs in cell culture as cell growth factor. Besides, it seemed that MRJP1 could promote liver regeneration and might have a cytoprotective action on hepatocytes. Here, we used Chang's liver cell from human as object to observe the proliferation action of MRJPs on the cell line, and to explore the potential of MRJPs substituting fetal bovine serum (FBS) as growth factor; the active mechanism of MRJPs was also investigated.MRJPs were extracted by centrifuging from fresh royal jelly. The optimum concentration was selected by MTT assaying of the proliferation rates of the cell (PRC) cultured with serum-free mediums containing 0.05, 0.1, 0.2, 0.3 and 0.5 mg/mL of MRJPs at 5th day. The possibility of MRJPs with optimum concentration (0.5 mg/mL) to replace FBS was investigated via comparison of the effects on PRC at the 2nd day, 5th day and 8th day in both serum-free and serum-existing mediums with a positive control containing 10% FBS and a negative control containing 10% phosphate buffer solution (PBS).