Isolation,Purification And Identification Of Astragalus Mongholicus Polysaccharides And Study On The Mitigating Effects Against Diabetes Nephropathy

Astragalus Mongholicus polysaccharides(m APS),one of the effective components in the Leguminosae of Rosidae,have been widely recognized as having pharmacological effects such as lowering blood glucose,anti-oxidation and anti-inflammation.In this experiment,m APS were isolated and purified from Astragalus mongholicus Bunge.,and their characteristics were analyzed.The results showed that the polysaccharides components of m APS1,m APS2 and m APS3 were isolated by water extraction and ethanol precipitation.The yield of m APS1,m APS2 and m APS3 were 1.29%,5.54% and 3.78%,respectively.The glucose content was 57.1%,72.8% and 63.6%,respectively,as determined by phenol-sulfuric acid method.Compared with m APS1 and m APS3,the structure of m APS2 was more compact and porous.After purification by Sephadex-G100,m APS2 and m APS3 exhibited smooth arcs at the full wavelength of UV.There are characteristic absorption peaks of methylene,carboxyl or Aldehyde,and pyranose in m APS2 and m APS3 as analyzed by the Fourier Transform infrared spectrum.ABTS and DPPH free radical scavenging experiments showed that m APS2 and m APS3 had better free radical scavenging effect than that of m APS1.Type 2 diabetes Mellitus(T2DM)is a complex metabolic disease with many complications.Diabetic nephropathy(DN)is one of the most common microvascular complications and major cause of death in diabetes Mellitus.Because of its complex pathogenesis,there is no specific therapeutic drug.In recent years,studies have shown that the treatment of traditional Chinese medicine demonstrates effective treatment against DN with less side effects.In this experiment,we studied the mitigation effects and mechanisms of m APS against DN.Sixty male sprague-dawley rats were random Ly divided into 5 groups: Control Group(Ctrl),m APS control group(m APS,200 mg/kg),model group(T2DM),m APS treatment group(T2DM + m APS,200 mg/kg),metformin treatment group(T2DM + MET,300mg/kg),except the Ctrl Group and m APS group,the other three groups were fed with high-sugar and high-fat diet for 4 weeks.After fasting for 12 hours,streptozotocin(STZ)(35mg/kg)was injected intraperitoneally.One week later,the T2 DM model was considered successful when the fasting blood glucose was higher than 11.1 mmol/l.m APS(200mg/kg)or Metformin(MET,300 mg kg)were given intragastrically for 4 weeks.The results showed that the body weight,food intake and water intake of T2 DM rats were significantly improved(p<0.05),the blood glucose level was significantly decreased(p<0.05),and the HOM-IR index was significantly decreased(p<0.05)after m APS treatment.The levels of serum triglyceride(TG),total cholesterol(TC)and Low-density Lipoprotein cholesterol(LDL-C)were significantly decreased(p<0.05),while the levels of high-density lipoprotein cholesterol(HDL-C)were significantly increased(p<0.05)in m APS treated rats.m APS also significantly reduced kidney weight,kidney-to-body ratio,and Serum Urea Nitrogen(BUN),creatinine(CR),and uric acid(UA)(p<0.05).The histopathology results showed that m APS treatment leads to reduced vacuolation and inflammatory cell infiltration of renal tubules in DN rats.Masson staining showed that m APS could reduce the deposition of renal cellulose in DN rats.After m APS supplementation,the content of MDA in serum of DN rats was significantly decreased(p<0.05),while the content of GSH and GSH-px was significantly increased(p<0.05).The m RNA and protein expression levels of Nrf-2,HO-1,SOD-2 and NQO-1 in renal tissue were also significantly increased(p<0.05).Further studies showed that m APS significantly decreased the levels of LPS,IL-1β and TNF-α in serum of T2 DM rats(p<0.05).m APS down-regulated the expression of TLR4,NLRP3 and p-NF-κB in renal tissue of T2 DM rats.The m RNA expression levels of TLR4,NLRP3,IL-1β and TNF-α were also decreased after m APS treatment.Conclusion: m APS2,an antioxidant component of Astragalus mongholicus polysaccharides,was isolated and purified from Astragalus mongholicus Bunge.m APS ameliorates T2DM-induced diabetic nephropathy through antioxidant and anti-inflammatory effects.