Simple and versatile in situ thermo-sensitive hydrogel for rectal administration of SZ-A to alleviate inflammation and repair mucosal barrier in ulcerative colitis

Ulcerative colitis(UC)is a chronic inflammatory bowel disease characterized by persistent inflammation of the colon and disrupted intestinal function.Ramulus mori(Sangzhi)alkaloids(SZ-A),derived from twigs of mulberry,were approved by the National Medical Products Administration in 2020 for treating type 2 diabetes mellitus.Accumulated evidence has confirmed that SZ-A also alleviates non-alcoholic fatty liver disease and ameliorates inflammation,indicating its potential to address inflammation in UC.However,the treatment of UC faces challenges due to low drug delivery efficiency and short retention time.To overcome these challenges,an injectable and adherent in-situ thermo-sensitive hydrogel containing SZ-A was developed for rectal drug delivery,utilizing the thermo-sensitive polymers Poloxamer 407and 188.The thermo-sensitive hydrogel system was designed with a moderate gelation temperature of 32±0.5℃,a short gelation time of 64 s,a p H range of 7-10,high moisturizing capability exceeding 90%,and moderate mechanical strength of 4-5 s.In a rat model with UC,the in situ thermo-sensitive hydrogel significantly extended the retention time at the colonic site and enabled sustained release after rectal administration.Symptoms of UC were markedly reduced following rectal administration of SZ-A thermosensitive hydrogel.Furthermore,the release of inflammatory factors,such as interleukin-1β(IL-1β),IL-6,IL-18,tumor necrosis factor-α(TNF-α),and transforming growth factor-β1(TGF-β1),significantly decreased in the SZ-A thermo-sensitive hydrogel group.The integrity of the colonic mucosal barrier was significantly enhanced following the application of SZ-A thermo-sensitive hydrogel.In conclusion,rectal administration of SZ-A in situ thermo-sensitive hydrogel effectively alleviated UC symptoms,inhibited the secretion of inflammatory factors,and promoted the repair of the colonic mucosal barrier.This approach holds promise as a potential treatment for UC.

Gas-propelled nanomotors alleviate colitis through the regulation of intestinal immunoenvironment-hematopexis-microbiota circuits

The progression of ulcerative colitis(UC)is associated with immunologic derangement,intestinal hemorrhage,and microbiota imbalance.While traditional medications mainly focus on mitigating inflammation,it remains challenging to address multiple symptoms.Here,a versatile gas-propelled nanomotor was constructed by mild fusion of post-ultrasonic CaO_(2) nanospheres with Cu_(2)O nanoblocks.The resulting CaO_(2)–Cu_(2)O possessed a desirable diameter(291.3 nm)and a uniform size distribution.It could be efficiently internalized by colonic epithelial cells and macrophages,scavenge intracellular reactive oxygen/nitrogen species,and alleviate immune reactions by pro-polarizing macrophages to the anti-inflammatory M2 phenotype.This nanomotor was found to penetrate through the mucus barrier and accumulate in the colitis mucosa due to the driving force of the generated oxygen bubbles.Rectal administration of CaO_(2)–Cu_(2)O could stanch the bleeding,repair the disrupted colonic epithelial layer,and reduce the inflammatory responses through its interaction with the genes relevant to blood coagulation,anti-oxidation,wound healing,and anti-inflammation.Impressively,it restored intestinal microbiota balance by elevating the proportions of beneficial bacteria(e.g.,Odoribacter and Bifidobacterium)and decreasing the abundances of harmful bacteria(e.g.,Prevotellaceae and Helicobacter).Our gas-driven CaO_(2)–Cu_(2)O offers a promising therapeutic platform for robust treatment of UC via the rectal route.