The Droliferation And Anti-senescence Effects Of The Major Royal Jelly Proteins On HFL-I Cell Line

Royal jelly(RJ),secreted by hypopharyngeal and mandibular glands of nurse honeybees(Apis mellifera),is the unique food for honeybee queen and the food for honeybee larvae during the first 3 days in their lifespan,respectively.Approximately 50%of the dry mass of RJ belongs to protein,among which 80%belongs to the major royal jelly proteins(MRJPs).Previous studies have shown that MRJPs possess several kinds of bioactivities,including anti-oxidation,antihypertensive activity,immunoregulatory activity,growth-promoting effect and anti-senescence effect.Moreover,MRJPs are supposed to be the key factor for the caste differentiation process of honey bees.However,the question if MRJPs possess anti-senescence activity for human cells remains.Human embryonic lung fibroblast cell line(HFL-I)as the aging model was used in our studies.HFL-I cells were supplied media containing either no MRJPs(A,CK),or MRJPs at 0.1 mg/mL(B,w/v),0.2 mg/mL(C),0.3 mg/mL(D),or bovine serum albumin(BSA)at 0.2 mg/mL(E).The results of proliferation activity assay demonstrated that HFL-I cells in medium C possessed the highest proliferation activity,and the growth-promoting effect was positively associated with the concentration of MRJPs within a certain range.Proliferation curves further indicated that MRJPs increased the proliferation rate of HFL-I cells.Cells in MRJPs media showed shorter passage intervals after the 8th passage compared to CK,demonstrating that MRJPs suppressed the loss of proliferation ability.Cellular morphological observation showed that the manifestation of HFL-I cells was influenced by MRJPs.Majority of the cells in the medium C and D were in healthy shape and good size,while others showed aging phenotype.The mean population doubling levels(PDL)of cells in medium B,C,D and E were increased by 12.4%,31.2%,24.0%and 10.4%compared to that in medium A,respectively.The cells in medium C also possessed the lowest senescence associated with?-galactosidase(SA-?-gal)activity and the longest telomere length.Moreover,MRJPs upregulated expression level of anti-senescence gene,SOD1,and downregulated expression levels of aging related genes,mTOR,CTNNB1 and TP 53.The mean Raman spectra were roughly similar from each other.However,the bands at 1342 and 1536cm-1 were detected only on the spectrums of cells in MRJPs media,which were assigned to purine(guanine and adenine),and amide carbonyl group vibrations and aromatic hydrogens,respectively.Guanine and adenine are the materials of DNA replication.Amide carbonyl group and aromatic hydrogens are the compounds of proteins synthesis.Therefore,it could be inferred that MRJPs promote the synthesis of DNA and proteins in HFL-I cells.These results suggested that MRJPs possess anti-senescence activity for HFL-I cell line,and provided new knowledges to illustrate the molecular mechanism of MRJPs as anti-senescence factors.