Oral Administration of Cryptotanshinone-Encapsulated Nanoparticles for the Amelioration of Ulcerative Colitis.

BACKGROUND

Inappropriate macrophages phenotype transition contributes to the development of ulcerative colitis, and the poly (ethylene glycol)-block-poly (d, l-lactic acid) (PEG-PLA) nanoparticles delivery system can be utilized to improve the cryptotanshinone (CTS)-based therapy.

METHODS

We used a single emulsification method to prepare CTS-encapsulated nanoparticles (NP). The therapeutic efficacy of NP was evaluated in dextran sulfate sodium (DSS)-induced colitis mice. Then the proportion of total macrophages and M2-like macrophages were assayed with flow cytometry, and the relative content of pro-inflammatory cytokines in the colon was detected with Western blot. Bone-marrow-derived macrophages (BMDMs) were induced into M1-like macrophages, which were further incubated with NP to repolarize into M2 subtype

RESULTS

Cryptotanshinone could induce the transition of M1 subtype to M2 subtype as indicated by up-regulated expression of arginase 1 (ARG1), interleukin (IL)-10, and CD206. , orally administrated NP accumulated in the colon-infiltrated macrophages in colitis mice. It further revealed that NP significantly alleviated colitis symptoms as indicated by increased body weight and colon length, decreased tumor necrosis factor (TNF)-α, IL-1β, and IL-6 content in the colon, and diminished total macrophage proportion (CD45CD11bF4/80) and up-regulated M2 proportion (CD45CD11bF4/80CD206).

CONCLUSION

Oral administration of NP could ameliorate ulcerative colitis with the conversion of M1-like macrophages to M2-like macrophages.