Notoginsenoside R1 Ameliorate High-Fat-Diet and Vitamin D3-Induced Atherosclerosis via Alleviating Inflammatory Response, Inhibiting Endothelial Dysfunction, and Regulating Gut Microbiota

Abstract

Aim: Natural medicines possess significant research and application value in the field of atherosclerosis (AS) treatment. The study was performed to investigate the impacts of a natural drug component, notoginsenoside R1, on the development of atherosclerosis (AS) and the potential mechanisms.

Methods: Rats induced with AS by a high-fat-diet and vitamin D3 were treated with notoginsenoside R1 for six weeks. The ameliorative effect of NR1 on AS rats was assessed by detecting pathological changes in the abdominal aorta, biochemical indices in serum and protein expression in the abdominal aorta, as well as by analysing the gut microbiota.

Results: The NR1 group exhibited a noticeable reduction in plaque pathology. Notoginsenoside R1 can significantly improve serum lipid profiles, encompassing TG, TC, LDL, ox-LDL, and HDL. Simultaneously, IL-6, IL-33, TNF-α, and IL-1β levels are decreased by notoginsenoside R1 in lowering inflammatory elements. Notoginsenoside R1 can suppress the secretion of VCAM-1 and ICAM-1, as well as enhance the levels of plasma NO and eNOS. Furthermore, notoginsenoside R1 inhibits the NLRP3/Cleaved Caspase-1/IL-1β inflammatory pathway and reduces the expression of the JNK2/P38 MAPK/VEGF endothelial damage pathway. Fecal analysis showed that notoginsenoside R1 remodeled the gut microbiota of AS rats by decreasing the count of pathogenic bacteria (such as Firmicutes and Proteobacteria) and increasing the quantity of probiotic bacteria (such as Bacteroidetes).

Conclusion: Notoginsenoside R1, due to its unique anti-inflammatory properties, may potentially prevent the progression of atherosclerosis. This mechanism helps protect the vascular endothelium from damage, while also regulating the imbalance of intestinal microbiota, thereby maintaining the overall health of the body.

Keywords: endothelial damage; gut microbiota; inflammation; notoginsenoside R1.

Graphical abstract

Figure 1

The effects of Notoginsenoside R1 on (A) TC, (B) TG, (C) LDL, (D) HDL and (E) ox-LDL. The data are shown as the mean ± SD (n = 8). ## p < 0.01, significantly different from control group. *p < 0.05 and ** p < 0.01, significantly different from model group.

Figure 2

Impact of notoginsenoside R1 administration on aortic histopathological features in rats (200×). The abdominal aorta was extracted promptly upon rat euthanasia. We conducted Oil Red O staining and H&E staining to visualize plaque size and lipid content.

Figure 3

The effects of Notoginsenoside R1 on (A) IL-6, (B) IL-33, (C) IL-1β and (D) TNF-α. Results are manifested as the mean ± SD (n = 8). ## p < 0.01 versus control group; **p < 0.01 versus model group (n = 8).

Figure 4

Impacts of notoginsenoside R1 on the adhesion molecule levels: (A)ICAM-1, (B)VCAM-1, (C)NO and (D)eNOS in AS rats. Results are expressed as the mean ± SD. ##p < 0.01 versus control group; **p < 0.01 versus model group (n = 8).

Figure 5

Notoginsenoside R1 inhibits activation and expression of NLRP3/Cleaved Caspase-1/IL-1β pathway in AS rats. (A) Expression levels of related protein expression were determined by the Western blot. Quantitative analysis of the expression of (B) NLRP3, (C) Cleaved Caspase-1, and (D) IL-1β, and β-Actin served as the internal control for protein analysis. All the values are represented by the means ± SD. ## p < 0.01 and # p < 0.05 versus control group; ** p < 0.01 and * p < 0.05 versus model group.

Figure 6

Notoginsenoside R1 modulates the expression of proteins related to endothelial factors. (A) Expression levels of related protein expression were ascertained by the Western blot. Quantitative analysis of the levels of (B) JNK2, (C) P38 MAPK, and (D) VEGF expression, and β-Actin was used the internal control of proteins. All data points are expressed by the means ± SD. ## p < 0.01 and # p < 0.05 versus control group; ** p < 0.01 and * p < 0.05 versus model group.

Figure 7

Notoginsenoside R1-mediated changes of gut microbiota in HFD combined with VD3-induced AS rats (n = 5). (A) Chao 1 indexes. (B) Shannon indexes. (C) Simpson indexes. (D) Heat map analysis of species composition. (E) Species compositions at the phylum level and (F) Principal coordinate analysis (PCoA) of all samples by weighted UniFrac distance.