Dectin1 activation of β-(1-3)/(1-6)-D-glucan produces an anti-mastitis effect in rats

Objective A lipopolysaccharide (LPS)-induced mastitis model in rats was used to study the protective effect of beta-glucan. Materials and methods On gestation day 10, beta-glucan was administered to rats daily by gavage at either 0 (control), 0.1 mg/kg BW, 1 mg/kg BW and 10 mg/kg BW until parturition. LPS or pyrogen-free physiological saline was inoculated into the mammary gland 72 h after parturition and the rats were euthanized at 12 h post-infection. Results LPS increased dectin1 and toll-like receptor 4 (TLR4) mRNA and protein expression significantly in mammary tissues. Tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, N-acetyl-beta-D-glucosaminidase (NAGase), inducible nitric oxide synthase (iNOs) in mammary tissues and serum, and myeloperoxidase (MPO) in mammary tissues were significantly increased 12 h after LPS infusion. beta-glucan administration could enhance dectin1 mRNA and protein expression while downregulating the expression of TLR4. Level of TNF-alpha, IL-1 beta in mammary tissues and serum, MPO, NAGase and iNOs activity in mammary tissues was decreased, but the level of IL-2 in serum was increased by beta-glucan. Conclusion The results indicate that beta-glucan may protect mammary tissue against LPS-induced rat acute mastitis.