Cistanche Deserticola Polysaccharides Attenuates Diabetic Nephropathy in Mice By Affecting The Intestinal Flora And Inhibiting The Toll-Like Receptor 4/Nuclear Factor-κB Signaling Pathway Ⅲ

3 Discussion

DN is the main cause of chronic kidney disease and end-stage renal disease. Studies have found that increased intestinal permeability, imbalanced intestinal flora and increased inflammation levels are key factors in the progression of DN. They may promote the occurrence and development of DN by affecting kidney function and exacerbating the chronic inflammatory state of diabetes [14].

Cistanche Deserticola Extract For Laxtive From High-quality Raw Materials

CLICK TO GET MORE DETAILS

CDPs are one of the effective active ingredients of Cistanche deserticola. Fu Zhifei et al. [15] found through experiments that crude polysaccharides, high molecular weight and low molecular weight polysaccharides of Cistanche deserticola can regulate the diversity of intestinal flora, increase beneficial bacteria, especially promote the growth of Prevotella, and increase the production of short-chain fatty acids. By exploring the synergistic effect of polysaccharides and small molecules, it was found that CDPs can regulate intestinal microorganisms and help promote intestinal health. Gu Jingna et al. [16] found that CDPs can regulate the composition of intestinal flora, improve intestinal mucosal damage, increase the level of short-chain fatty acids, and improve the inflammation of postmenopausal osteoporosis. Gao Yuan et al. [17] showed that CDPs can improve cognitive function in D-galactose aging model mice by restoring the homeostasis of the gut microbiota-brain axis, thereby alleviating amino acid imbalance, peripheral inflammation and oxidative stress, and has the potential to treat cognitive impairment associated with gut microbial dysbiosis. In addition, CDPs can inhibit osteoclast differentiation and bone resorption induced by NF-κB receptor activating ligands [18]. However, there are few reports on whether CDPs can treat DN by regulating the gut microbiota.

Cistanche Deserticola Oral Extract For Laxitive

The development of DN is accompanied by intestinal flora disorders [19]. The normal human intestinal microbiota is composed of two major groups: Bacteroidetes and Firmicutes [20]. Increased CDPs increased the relative abundance of Bacteroidetes and reduced the relative abundance of Firmicutes. The F/B value was closer to the Control group and significantly different from the Model group.

Firmicutes and Bacteroidetes play an important role in glucose metabolism in the body. Firmicutes regulate the body's inflammatory response by producing butyrate, which affects the progression of DN. Bacteroidetes can degrade carbohydrates and polysaccharides in food and synthesize vitamins. The two promote host energy metabolism together. At the same time, the F/B value is related to maintaining homeostasis in the body. Disturbance of this ratio may lead to metabolic syndromes such as diabetes [21-22]. This shows that CDPs may promote host energy metabolism, reduce intestinal inflammation, and maintain metabolic balance by affecting the F/B value. At the genus level, the relative abundance of Allobaculum in the Model group was significantly reduced. Allobaculum can physiologically use carbohydrates to produce butyrate, which plays an important role in intestinal health and blood sugar regulation [23]. In addition, the relative abundance of Roseburia, Romboutsia, Ruminococcus_torques_group, and RF39 increased in the Model group. The increase in Roseburia and Romboutsia may have a functional effect on the host's ability to regulate inflammation [24]. Mendelian randomization analysis showed that the abundance of Ruminococcus_torques_group was negatively correlated with glomerular filtration rate and chronic kidney disease risk, revealing its potential role in the pathogenesis of chronic kidney disease[25]. RF39 is potentially pathogenic, and its increased abundance is one of the signs of intestinal microbial structure disorder[26]. CDPs can reduce the abundance of potential pathogens and increase the abundance of beneficial bacteria, affecting the structure of intestinal flora.

Cistanche Deserticola Oral Extract For Laxitive

Maintaining a balance of intestinal flora is essential for maintaining the function of the intestinal barrier and overall health. The physical barrier function of the intestinal mucosa is closely related to the tight junctions between intestinal epithelial cells. Among the tight junction-related proteins, ZO-1 plays an important monitoring role in the tight junction function, while Occludin can regulate the strength of the paracellular barrier [27]. Increased levels of intestinal-derived LPS play an important role in the occurrence of diabetes and related diseases [28]. Studies have shown that high sugar, inflammation, and vascular damage can cause pathological changes in the kidneys, leading to a decrease in glomerular filtration rate and accumulation of various toxins in the body's blood. The intestine becomes the main excretion route (especially in the colon). Toxins can destroy the original pH of the intestine and the innate intestinal barrier, leading to increased intestinal permeability in mice, allowing microorganisms and their products to enter the blood, resulting in increased LPS levels [29]. Reducing LPS content can help reduce the release of proinflammatory cytokines in diabetic mice, reduce oxidative stress levels, and improve kidney pathology [30]. In this study, the damage to intestinal epithelial cells in the colon tissue of mice treated with CDPs was alleviated, the degree of inflammatory infiltration was reduced, the expression of ZO-1 and Occludin proteins was upregulated, and the LPS level was reduced, indicating that CDPs can help improve the intestinal barrier function of DN mice, reduce intestinal mucosal permeability, and thus improve the inflammatory response state of DN mice, further illustrating the improvement effect of CDPs on intestinal barrier function.

TLRs are a class of conserved pattern recognition receptors in the innate immune system that can activate downstream inflammatory signaling pathways under the stimulation of external pathogens [31]. TLR4 is a key member of the TLRs family and plays a vital role in the occurrence of inflammatory responses [32]. As a downstream effector of the TLR4 signaling pathway, NF-κB exists in an inactive form under normal physiological conditions, and the heterodimer composed of NF-κB p65 and p50 is combined with the inhibitory protein IκBα [33]. However, under pathological conditions, IκB kinase can lead to specific phosphorylation of IκBα, prompting NF-κB p65 to transfer to the nucleus, thereby triggering the body to release inflammatory factors and produce inflammatory responses. Studies have shown that the TLR4/NF-κB signaling pathway plays an important role in acute kidney injury and chronic kidney disease [34]. Weng Xiang et al. [35] showed that CDPs can enhance immune activity by inducing dendritic cell maturation and inhibiting the TLR4/NF-κB pathway. This experiment found that CDPs can effectively reduce TLR4 protein expression in the renal tissue of DN mice, inhibit the phosphorylation of NF-κB p65 and IκBα, and reduce the level of inflammatory factors. This result suggests that CDPs may protect the renal function of DN mice by inhibiting the TLR4/NF-κB signaling pathway.

4 Conclusion

This study mainly focused on the effects of CDPs on the intestinal flora and intestinal barrier function of DN mice. Therefore, the intestinal flora sequencing focused on the Control group, Model group and CDPs-H group, which has certain limitations. However, it is clear that CDPs can improve DN by increasing the abundance of beneficial flora and reducing the abundance of potentially harmful flora, improving intestinal barrier function, reducing serum inflammatory factors and endotoxin levels, and reducing the expression of TLR4/NF-κB p65 signaling pathway proteins in kidney tissue. In later studies, it is planned to continue to improve the purification, monosaccharide composition analysis and structural characterization of Cistanche deserticola crude polysaccharides, and explore its mechanism of alleviating DN by regulating intestinal flora, laying an experimental foundation for the development of CDPs in the food and pharmaceutical industries.

References:

[1] UMANATH K, LEWIS J B. Update on diabetic nephropathy: core curriculum 2018[J]. American Journal of Kidney Diseases, 2018, 71(6): 884-895. DOI:10.1053/j.ajkd. 2017.10.026.

[2] SHEU N W, HUANG S H, WU D C, et al. Effects of Helicobacter pylori treatment on the incidences of autoimmune diseases and inflammatory bowel disease in patients with diabetes mellitus[J]. PLoS ONE, 2022, 17( 5): e0265323. DOI:10.1371/journal.pone.0265323.

[3] RYSZ J, FRANCZYK B, ŁAWIŃSKI J, et al. The impact of CKD on uremic toxins and gut microbiota[J]. Toxins, 2021, 13(4): 252. DOI:10.3390/toxins13040252.

[4] ZHU T, HU B Y, ZHANG Y Q, et al. The role of microbial metabolites in diabetic kidney disease[J]. Heliyon, 2023, 9(7): e17844. DOI:10.1016/j.heliyon.2023.e17844.

[5] MOSTERD C M, KANBAY M, VAN DEN BORN B J H, et al. Intestinal microbiota and diabetic kidney diseases: the role of microbiota and derived metabolites inmodulation of renal inflammation and disease progression[J]. Best Practice & Research Clinical
Endocrinology & Metabolism, 2021, 35(3): 101484. DOI:10.1016/
j.beem.2021.101484.
[6] Wang Li, Song Wei, Liu Xiaoxue, et al. Bioactivity of Cistanche deserticola Research progress on ingredients and efficacy[J]. Food Science and Technology, 2023, 48(2): 208-214. DOI:10.13684/j.cnki.
spkj.2023.02.032.
[7] Song Zhihong, Lei Li, Tu Pengfei. Cistanche spp. Research progress on the pharmacological activity of plants[J]. Chinese Herbal Medicine, 2003, 34(9): 16-18. DOI:10.3321/j.issn:0253-2670.2003.09.048.
[8] Tu Pengfei, Jiang Yong. Re-examination of the Materia Medica of Cistanche deserticola[J]. Chinese Journal of Traditional Chinese Medicine, 2022,47(20): 5670-5679. DOI:10.19540 /j.cnki.cjcmm.20220711.101