Abstract: Objective:To explore the effects of peptides produced from Spirulina protein hydrolyzed by pepsin on concentrations of IL-1β,IL-6,IL-12,IFN-γ,TNF-α,IL-1Ra,IL-4,IL-10 and TGF-β in rabbit serum. Methods: protein was extracted from Spirulina by salting out method,and then hydrolyzed by pepsin. The hydrolysate was administered to rabbits by gavage,intraperitoneal injection and ear vein injection respectively. At 3,2 and 2 h after administration respectively,ELISA kit was used to determine the concentration changes of IL-1β,IL-6,IL-12,IFN-γ,TNF-α,IL-1Ra,IL-4,IL-10 and TGF-β in rabbit serum. Results: The concentrations of IL-1β,IL-1Ra,IL-4,IL-6 and IL-12 decrease,but the concentrations of TNF-α,IFN-γ and IL-10 increase,and the concentration of TGF-β has no obvious change. In intraperitoneal injection group,concentrations of IL-4,TNF-α,IL-1Ra (also in ear vein injection injection group),IL-6 (also in ear vein injection injection group) and IL-1β have significant changes,which show that the peptides play an important regulatory role in the cytokine network by mucosal immune system. The effect of intraperitoneal injection is the most markable,followed by ear vein injection and gavage administration successively. As a whole,the concentrations of most cytokines decrease,but the concentrations of TNF-α,IFN-γ and IL-10 increase. It suggests that the peptides produced from Spirulina protein hydrolyzed by pepsin play an important regulatory role for body immune function by regulating cytokines level. Conclusion: Among the three administra-tion methods,the intraperitoneal injection has the most obvious effects,because direct administration to intestinal mucosal is possibly the most effective way. So the peptides produced from Spirulina protein hydrolyzed by pepsin have the promise of drug development.

Key words: Spirulina protein, cytokine, immune regulation