Abstract: Objective To investigate the prophylactic effects of pretreatment with baicalin on erythrocyte alloimmunization. Methods A model of red blood cell (RBC) infusion was established in C57BL/6 mice through co-infusion of human RBCs and lipopolysaccharide (LPS) as an adjuvant. Mice were randomly assigned into four experimental groups: (1) RBC infusion model group; (2) Untreated control group: injection of PBS only; (3) Baicalin pretreatment group: mice were given baicalin (250 mg/（kg·day）) daily for one week prior to the establishment of the RBC infusion model; (4) Dexamethasone (DEX) control group: DEX (5 mg/（kg·day）) were given daily for one week prior to the establishment of the RBC infusion model. The expression levels of IgG and IgM in the mice serum were analyzed by flow cytometry, and changes in CD4 T cells and B cells in the spleen were monitored. Results Compared to the RBC infusion model group, baicalin pretreatment significantly reduced the production of serum IgG (24 823.0±1 452.2 vs. 15 180.0±1 172.5, P<0.05) and IgM (194 206±2 868.6 vs. 112 287±9 741.5, P<0.05). Compared with the model group, there was a significant decrease in the expression of CD25 (1 006.0 ±206.1 vs. 548.4±19.1, P<0.05) and the proportion of B cells (31.16%±6.06% vs. 15.69%±4.59%, P<0.05) in the spleens of baicalin-pretreated mice, and no significant difference in the spleen size (mean length: 10±0.5 mm vs. 12±0.5 mm, P>0.05). Conclusion Baicalin effectively suppresses erythrocyte alloimmunization by inhibiting the production of IgG and IgM in the serum, as well as the inhibition of B cell proliferation and CD4 T cell activation in the spleen.

Key words: Baicalin, Erythrocyte alloimmunization, Antibody production