Multifunctional MnGA Nanozymes for the Treatment of Ulcerative Colitis by Reducing Intestinal Inflammation and Regulating the Intestinal Flora.

In ulcerative colitis (UC), the formation of an inflammatory environment is due to the combined effects of excess production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), overproduction of proinflammatory cytokines, and disruption of immune system function. There are many kinds of traditional drugs for the clinical treatment of UC, but long-term drug use can cause toxic side effects and drug resistance and can also reduce patient compliance and other drawbacks. Hence, in light of the clinical challenges associated with UC, including the limitations of existing treatments, intense adverse reactions and the development of resistance to medications, no novel therapeutic agents that offer effective relief and maintain a high level of biosafety are urgently needed. Although many anti-inflammatory nanomedicines have been developed by researchers, the development of efficient and nontoxic nanomedicines is still a major challenge in clinical medicine. Using the natural product gallic acid and the metal compound manganese chloride, a highly effective and nontoxic multifunctional nanoenzyme was developed for the treatment of UC. Nanozymes can effectively eliminate ROS and RNS to reduce the inflammation of intestinal epithelial cells caused by oxidation, facilitate the restoration of the intestinal epithelial barrier through the upregulation of tight junction protein expression, and balance the intestinal microbiota to maintain the stability of the intestinal environment. Using a rodent model designed to mimic UC, we monitored body weight, colon length, the spleen index, and the degree of tissue damage and demonstrated that manganese gallate (MnGA) nanoparticles can reduce intestinal inflammation by clearing ROS and active nitrogen. Intestinal flora sequencing revealed that MnGA nanoparticles could regulate the intestinal flora, promote the growth of beneficial bacteria and decrease the levels of detrimental bacteria within the intestinal tract in a mouse model of UC. Thus, MnGA nanoparticles can maintain the balance of the intestinal flora. This study demonstrated that MnGA nanoparticles are excellent antioxidant and effective anti-inflammatory agents, have good biosafety, and can effectively treat UC.