Macrophage-Targeted Berberine-Loaded β-Glucan Nanoparticles Enhance the Treatment of Ulcerative Colitis

Abstract

Aim: This study focuses on constructing of an anti-inflammatory drug delivery system by encapsulation of berberine in the β-glucan nanoparticles and evaluates its effect on treating ulcerative colitis.

Methods: β-Glucan and the anti-inflammatory drug berberine (BER) are self-assembled into nanoparticles to construct a drug delivery system (GLC/BER). The interaction between the drug and the carrier was characterized by circular dichroism, ultraviolet-visible spectroscopy, and dynamic light scattering. The anti-inflammatory effect of the GLC/BER was evaluated through a lipopolysaccharide (LPS)-induced RAW264.7 macrophage inflammation model and a sodium sulfate (DSS)-induced C57BL/6 mouse ulcerative colitis model.

Results: The GLC/BER nanoparticles have a particle size of 80-120 nm and a high encapsulation efficiency of 37.8±4.21%. In the LPS-induced RAW264.7 macrophage inflammation model, GLC/BER significantly promoted the uptake of BER by RAW264.7 cells. RT-PCR and ELISA assay showed that it could significantly inhibit the inflammatory factors including IL-1β, IL-6 and COX-2. Furthermore, GLC/BER shows inhibiting effect on the secretion of pro-inflammatory factors such as IL-1β and IL-6, down-regulating the production of nitrite oxide; in animal studies, GLC/BER was found to exert a relieving effect on mice colitis.

Conclusion: The study found that GLC/BER has an anti-inflammatory effect in vitro and in vivo, and the GLC carrier improves the potency and bioavailability of BER, providing a new type of nanomedicine for the treatment of colitis.

Keywords: anti-inflammation; chiral; drug carrier; immunoregulation; β-glucan.

Figure 1

The preparation of GLC/BER and the proposed therapeutic effect on colitis.

Figure 2

Characterizations of GLC and GLC/BER. Photographs of GLC, BER and GLC/BER in solution, Inset: TEM images of the nanoparticles (A); DLS results and particle size distribution of GLC and GLC/BER (B); UV spectrum analysis of BER and GLC/BER (C); CD spectra of BER and GLC/BER (D).

Figure 3

Cumulative release statistics of GLC/BER in vitro under different gastrointestinal conditions (48h).

Figure 4

The uptake of BER (A, C, E and G) and GLC/BER (B, D, F and H) in RAW264.7/Caco-2 cells was determined after incubation for 1h and 4h.

Figure 5

The effects of GLC, BER and GLC/BER on the mRNA expression of COX-2, IL-1β, IL-6 (A) and IL-1β, IL-6 (B) and NO (C) secretion of RAW264.7 macrophages induced by LPS after incubation for 12 hours. Each value represents the mean ±SEM of three separate experiments. Each group was compared with the cell blank control group. **p<0.01, ***p<0.001, ****p<0.0001.

Figure 6

Effects of GLC/BER on alleviating the symptoms of DSS-induced colitis in mice. Experimental protocol of DSS -nduced colitis in mice (A); Body weight change (B); DAI score (C); Statistical analysis of colon length (D); Representative view of colon (E). Data were presented as mean standard deviation (n=6). Each group was compared with the DSS group, *P<0.05, **P<0.01, ****P<0.0001.

Figure 7

H&E staining of colonic sections at 100 and 200 magnification. CTRL (A); DSS (B); DSS+GLC (C); DSS+BER (D); DSS+GLC/BER (E); Colon histopathological injury score (F). Organ tissue sections of control and GLC groups (G), *P<0.05, ***P<0.001.