Improvement Effect of Shiitake Glycoprotein against Lead Acetate-induced Toxicity in Rats

Objective: This study was conducted to investigate the purification process aimed at obtaining a shiitake glycoprotein with lead eliminating effect, and to explore its preventive and therapeutic efficacy against lead acetate-induced lead toxicity in a rat model. Methods: The crude polysaccharide was extracted from shiitake mushrooms using a hot water extraction method, followed by further purification involving protein removal and chromatography techniques to obtain the bioactive glycoprotein. The molecular characteristics of the glycoprotein were determined through various analytical methods, including infrared spectroscopy analysis, monosaccharide composition analysis, N-terminal amino acid sequencing, and internal amino acid sequence analysis. To evaluate the bioactive potential of shiitake polysaccharide-peptide in addressing lead poisoning in rats, 63 male Sprague-Dawley rats were randomly distributed into nine groups, including a control group, a model group, a positive control group, and shiitake glycoprotein treatment groups at doses of 4, 8 and 160 mg/kg, as well as shiitake fruiting body treatment groups at doses of 4, 12 and 36 g/kg. Lead poisoning was induced in the rats via intraperitoneal injection of lead acetate. The rats were administered polysaccharide-peptide and shiitake fruiting body treatments for a duration of 30 days, with observations made regarding their physical condition. Parameters assessed included body weight, lead content in blood and various organs, as well as biochemical markers in serum. Results: The monosaccharide composition analysis showed that the purified shiitake glycoprotein (LEPP) was composed of glucose, mannose, galactose, glucuronic acid, xylose, fucose, ribose, galacturonic acid, arabinose and rhamnose. The amino acid sequence analysis showed that the N-terminal sequence was MPEQVVVADA, indicating that the shiitake glycoprotein had polysaccharide and protein components. The findings indicated that shiitake glycoprotein effectively promoted weight gain in rats afflicted with lead poisoning. It significantly reduced lead concentrations in both blood and liver, mitigated lead deposition within the liver, enhanced the activities of superoxide dismutase (SOD) and catalase (CAT) in the serum, lowered the levels of malondialdehyde (MDA) （P<0.05）, and improved overall antioxidant capacity. Moreover, shiitake glycoprotein led to decreased levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the blood, signifying its hepatoprotective qualities. Conclusion: In summary, shiitake glycoprotein exhibited the capability to remove the heavy metal lead from the body and ameliorate the symptoms of lead poisoning in the rat model.