Comparison of Allergic Parameters between Whey Protein Concentrate and Its Hydrolysate in Rat Basophilic Leukemia (RBL)-2H3 Cells

This study was conducted to compare the anti-allergic effects of a whey protein concentrate (WPC) and WPC hydrolysate. WPC hydrolysate was prepared using enzymatic digestion for 8 h with trypsin and ${\alpha}$-chymotrypsin, after which it was freeze-dried. The allergic parameters assessed in rat basophilic leukemia (RBL)-2H3 cells were degranulation and release of ${\beta}$-hexosaminidase, release of tumor necrosis factor $(TNF)-{\alpha}$, and changes in the expression of $IL-1{\beta}$, IL-4, and IL-10 by real time polymerase chain reaction (PCR). During preparation of the WPC hydrolysate, hydrolysis increased rapidly from 0 to 10 min and then gradually increased slowly from 1 h onwards, achieving a final degree of hydrolysis of 78.50%. The SDS-PAGE analysis revealed a reduction in the intensity of several protein bands in the WPC hydrolysate compared to the WPC. IgE-induced ${\beta}$-hexosaminidase release from RBL-2H3 cells was decreased to a higher degree following treatment with the hydrolysate compared to WPC treatment. W500 ($500{\mu}g/mL$ WPC) showed the least inhibition of ${\beta}$-hexosaminidase release, but there was no significant difference between W500 and W1000 ($1,000{\mu}g/mL$) (p<0.05). H1000 ($1,000{\mu}g/mL$ WPC hydrolysate) inhibited ${\beta}$-hexosaminidase release by 39%. Compared to the control, treatment with H1000 decreased $TNF-{\alpha}$ secretion to 11.87 pg/mL. The gene expression levels of IL-1${\beta}$, IL-4, and IL-13 were all significantly decreased in hydrolysate (p<0.05). In the case of $IL-1{\beta}$ and IL-4, the expression levels in W1000 treated cells were decreased by 73.67% and 65%, respectively, and that of IL-13 was decreased by 66.43% compared to the control.