Abstract:

Objective: This study aimed to examine the immune-regulatory effect and acute toxicity of Agaricus blazei
polysaccharide in mice. Methods: The effects of Agaricus blazei polysaccharide on immunological organs in mice and the
ability of the reticuloendothelial system to clear inert carbon particles from bloodstream were observed in order to explore
the immunoregulatory effect on mammals. By using an improved Karber’s method, the acute toxicity of Agaricus blazei
polysaccharide was studied. Results: Agaricus blazei polysaccharide (77–150 mg/kg, ig, 7 d) could promote cell proliferation
in the thymus and spleen. Agaricus blazei polysaccharide at 120 mg/kg caused an increase in proliferation rates of thymus
and spleen of 13.1% and 8.5% for juvenile mice and of 4.0% and 18.3% for adult mice, respectively. Agaricus blazei
polysaccharide at 150 mg/kg increased the phagocytic index by 21.7% in the carbon particle clearance test, and enhanced the
corrected phagocytic index by 11.8% in mice, indicating that Agaricus blazei polysaccharide can promote immune function
in mice. The LD50 of Agaricus blazei polysaccharide by intravenous injection was 840.8 mg/kg, equivalent to intravenous
injection of 6.5 g of Agaricus blazei polysaccharide into an adult one time. After two weeks, the body weight of the survived
mice was increased by 61.1% on average. After oral administration of Agaricus blazei polysaccharide at 15.0 g/kg, only mild
discomfort occurred and all mice were alive. This dose is relatively equivalent to an intake of 115.4 g of Agaricus blazei
polysaccharide for adults per day, and is also equivalent to an ingestion of 881–1 265 g of Agaricus blazei. Conclusion:
Agaricus blazei polysaccharide can enhance immune function in mice with minimal acute toxicity.

Key words: Agaricus blazei polysaccharide, immunoregulation, acute toxicity, improved Karber’s method