The Rhei radix rhizoma-based carbon dots ameliorates dextran sodium sulphate-induced ulcerative colitis in mice

Figures & data

Figure 1. Preparation of Rhei radix et rhizoma-based carbon dots. The flowchart for the preparation process of carbon dots is derived from Rhei radix et rhizoma carbonisata.

Table 1. Disease activity index^b.

Score	Weight loss(%)^a	Stool shape	Occult/grave blood
0	0	Normal	Negative
1	1–5	Loose stool	–
2	5–10	Loose stool	Hemoccult positive
3	10–15	Diarrhoea	–
4	>15	Diarrhoea	Grave blood

^aBased on the weight before modelling, percentage weight loss = (basal body weight (g) - daily mouse body weight (g))/basal body weight (g) × 100%.

^bDisease activity index = (percentage weight loss + stool shape score + occult/grave blood score)/3.

Figure 2. Characterization of Rhei radix et rhizoma-derived carbon dots. (A) Low-resolution transmission electron microscope image. Inset: Histogram of particle size distribution. (B) XRD pattern. (C) Ultraviolet visible specturm. (D) High-resolution transmission electron microscope image. (E) Excitation and emission fluorescence spectra. (F) Fourier transform infrared spectroscopy.

Figure 3. X-ray photoelectron spectroscopy of Rhei radix et rhizoma-carbon dots. (A) Full-scan X-ray photoelectron spectrum of Rhei radix et rhizoma carbonisata-derived carbon dots. High-resolution measurement spectra of (B) C 1s, (C) O 1s, (D) N 1s.

Figure 4. Cytotoxicity analysis in RAW264.7 cells treated with various doses of carbon dots derived from Rhei radix et rhizoma.

Figure 5. Hemostatic time of Rhei radix et rhizoma-carbon dots. Control: normal saline; HC: Hemocoagulase; H, M, L: high-, medium-, and low-dose (0.23, 0.12, and 0.06 mg/kg) RRR-CD-treated groups, respectively. **P<0.01 compared with the control group. 

Figure 6. Effects of Rhei radix et rhizoma-carbon dots on DSS-induced UC in mice. (A) Experimental schedule of the DSS-induced UC model in mice. (B) Body weight changes. (C) DAI score. (D) Colon length histogram. (E) Colon tissue photographs.Control: normal saline; SASP: Sulfasalazine; H, M, L: high-, medium-, and low-dose (0.23, 0.12, and 0.06 mg/kg) RRR-CDs-administered groups, respectively. Values are means ± SD, *p<0.05; **p<0.01 compared with the model group; ##p<0.01 compared with the control group. 

Figure 7. Rhei radix et rhizoma-carbon dots ameliorate the histological changes of DSS-induced UC in mice. Histopathological sections of each group (A-F) were stained with H&E, scale bar = 50μm, 200×; 100μm, 400×. (A) Control group [normal saline]. (B) Model group [DSS]. (C) Positive group [Sulfasalazine]. (D) RRR-CDs High-does group. (E) RRR-CDs Mediun-dose group. (F) RRR-CDs Low-dose group.

Figure 8. Effects of Rhei radix et rhizoma-carbon dots on the level of TNF-α, IL-6, and IL-10 in colon tissue. Mice were treated with NS, SASP, and different concentrations of Rhei radix et rhizoma carbonisata-derived carbon dots (H: 0.23; M: 0.12, L: 0.06 mg/kg). ##p<0.01 compared with the control group; *p<0.05; **p<0.01 compared with the model group. Values are means ± SD. Control: normal saline; SASP: Sulfasalazine; H: RRR-CDs high dose; M: RRR-CDs medium dose; L: RRR-CDs low dose. 

Figure 9. Effects of Rhei radix et rhizoma-carbon dots on the level of SOD, CAT, GSH, MPO, and MDA in colon tissue. Mice were treated with NS, SASP, and different concentrations of Rhei radix et rhizoma carbonisata-derived carbon dots (H:0.23; M:0.12, L:0.06 mg/kg). ##p<0.01 compared with the control group; *p<0.05; **p<0.01 compared with the model group. Values are means ± SD. Control: normal saline; SASP: Sulfasalazine; H: RRR-CDs high dose; M: RRR-CDs medium dose; L: RRR-CDs low dose. 

Figure 10. The expression of tight junction proteins in the intestinal tract of mice with UC. Antigen-antibody binding-stained sections. Scale bar = 20μm, 630×. Control: normal saline; SASP: Sulfasalazine; H, M, L: high-, medium-, and low-dose (0.23, 0.12, and 0.06 mg/kg) RRR-CDs-administered groups, respectively. 

Data availability statement

All data generated or analysed during this study are included in this published article.