Modulating effects of Astragalus polysaccharide on immune disorders via gut microbiota and the TLR4/NF-κB pathway in rats with syndrome of dampness stagnancy due to spleen deficiency

The syndrome of dampness stagnancy due to spleen deficiency(DSSD)is relatively common globally.Although the pathogenesis of DSSD remains unclear,evidence has suggested that the gut microbiota might play a significant role.Radix Astragali,used as both medicine and food,exerts the effects of tonifying spleen and qi.Astragalus polysaccharide(APS)comprises a macromolecule substance extracted from the dried root of Radix Astragali,which has many pharmacological functions.However,whether APS mitigates the immune disorders underlying the DSSD syndrome via regulating gut microbiota and the relevant mechanism remains unknown.Here,we used DSSD rats induced by high-fat and low-protein(HFLP)diet plus exhaustive swimming,and found that APS of moderate molecular weight increased the body weight gain and immune organ indexes,decreased the levels of interleukin-1β(IL-1β),IL-6,and endotoxin,and suppressed the Toll-like receptor 4/nuclear factor-κB(TLR4/NF-κB)pathway.Moreover,a total of 27 critical genera were significantly enriched according to the linear discriminant analysis effect size(LEfSe).APS increased the diversity of the gut microbiota and changed its composition,such as reducing the relative abundance of Pseudoflavonifractor and Paraprevotella,and increasing that of Parasutterella,Parabacteroides,Clostridium XIVb,Oscillibacter,Butyricicoccus,and Dorea.APS also elevated the contents of short-chain fatty acids(SCFAs).Furthermore,the correlation analysis indicated that 12 critical bacteria were related to the body weight gain and immune organ indexes.In general,our study demonstrated that APS ameliorated the immune disorders in DSSD rats via modulating their gut microbiota,especially for some bacteria involving immune and inflammatory response and SCFA production,as well as the TLR4/NF-κB pathway.This study provides an insight into the function of APS as a unique potential prebiotic through exerting systemic activities in treating DSSD.

Therapeutic Effect of Crocin on Diabetic Retinopathy in Rats Based on TLR4/My D88/NF-κB Pathway

Objective:To study the therapeutic effect of crocin on diabetic retinopathy(DR)in rats based on toll-like receptor 4(TLR4)/myeloid differentiation factor 88(My D88)/nuclear factor-κB(NF-κB)pathway.Methods:Thirty SPF SD rats were used in the experiment,which were randomly divided into DR group,control group and crocin group,with 10 rats in each group.The DR rat model was established by feeding the rats in both the DR group and crocin group with a high glucose and high fat diet,along with intraperitoneal injection(IP)of streptozotocin.Crocin IP was administered to the rats in the crocin group,whereas the rats in the DR group and control group received an equivalent dosage of saline IP for 12 weeks.A comparison was made among the three groups regarding retinal thickness,vascular permeability,expression of TLR4/My D88/NF-κB pathway protein,levels of inflammatory factors,and levels of Bcl-2,Bax,and Bcl-2/Bax.Results:The DR group and crocins group exhibited a lower retinal thickness compared to the control group,while the crocins group displayed a higher thickness than the DR group.The DR group and crocins group had higher retinal vascular permeability than the control group,and the crocins group had lower retinal vascular permeability than the DR group(P<0.05).TLR4,My D88,and P-NF-κB relative expressions were higher in the DR and crocin groups than in the control group,whereas TLR4,My D88,and P-NF-κB relative expressions were lower in the crocin group than in the DR group(P<0.05).The DR group and crocin group exhibited elevated levels of inflammatory cytokines compared to the control group,while the crocin group displayed decreased levels in comparison to the DR group(P<0.05).The DR group and crocin group exhibited lower levels of Bcl-2 and Bcl-2/Bax compared to the control group,whereas the control group displayed higher levels of Bax.The crocin group exhibited elevated levels of Bcl-2 and Bcl-2/Bax compared to the DR group,whereas the DR group displayed diminished levels of Bax(P<0.05).Conclusion:Crocin has the potential to enhance the retinal thickness and vascular permeability of DR rats,and the inhibition of the TLR4/My D88/NF-κB pathway by crocin could play a crucial role in impeding the advancement of DR.