香菇糖蛋白对大鼠铅中毒的改善作用

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

目的:通过优化提取工艺获得具有促排铅功能的香菇糖蛋白,探讨其对醋酸铅诱导铅中毒大鼠的防治效果。方法:利用热水浸提去除蛋白以及层析技术获得香菇糖蛋白纯品,利用红外光谱分析、单糖组成、N端氨基酸及内部氨基酸序列分析技术鉴定了香菇糖蛋白的分子特性。将63只雄性SD大鼠随机分为9组,即空白对照组、模型组、阳性对照组、香菇糖蛋白处理组(4、8、160 mg/kg)和香菇子实体处理组(4、12、36 g/kg),通过腹腔注射醋酸铅制备大鼠铅中毒模型,连续给药30 d,观察大鼠的外观表现,检测体重变化、血液和脏器中的铅含量以及生化指标。结果:提纯的香菇糖蛋白(LEPP)经过单糖组成分析发现其是由葡萄糖、甘露糖、半乳糖、葡萄糖醛酸、木糖、岩藻糖、核糖、半乳糖醛酸、阿拉伯糖、鼠李糖组成,氨基酸序列分析发现其N端序列为MPEQVVVADA,说明香菇糖蛋白具有多糖和蛋白的成分。动物实验表明,香菇糖蛋白能够促进铅中毒大鼠的体重增长,显著降低血液和肝脏中铅的含量(P<0.05),具有排除铅在肝脏中的沉积作用,显著提高血清中超氧化物歧化酶(Superoxide Dismutase,SOD)和过氧化氢酶(Catalase,CAT)的活性(P<0.05),降低丙二醛(Malondialdehyde,MDA)的含量(P<0.05),提高机体的抗氧化能力,同时香菇糖蛋白还可以降低血液中谷草转氨酶(Glutamic Oxaloacetic Transaminase,AST)和谷丙转氨酶(Glutamic-Pyruvic Transaminase,ALT)的水平,具有保护肝脏的作用。结论:香菇糖蛋白可以排除体内的重金属铅,有效地改善大鼠的铅中毒症状。

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.