Synthesis and evaluation of anti‐inflammatory properties of hydroxyapatite nanoparticles in an experimental model of colitis

Ulcerative colitis (UC) is a chronic large intestinal condition, for treatment and prevention of which sulfasalazine (SSZ) is used. It functions by helping to reduce inflammation and other disease symptoms within the bowels, but this drug has many side effects. Various novel paths for UC treatment are being studied to solve the difficulties associated with present treatments and to design a more targeted therapy. Hydroxyapatite nanoparticles (HAP-NPs) form an inorganic portion of the natural bone and are primarily used in tissue engineering due to their anti-inflammatory and anti-toxicity character. This study aimed to investigate the anti-inflammatory character of sulfasalazine-containing HAP (SSZ-HAP-NPs) as a potential therapeutic agent.

The therapeutic efficacy of SSZ-HAP-NPs compared with SSZ as a standard drug was examined in a mouse model of colitis by induction of DSS for 7 days. Drugs were given on the third day and continued for seven days. Colonic mucosal inflammation was evaluated clinically, biochemically, and histologically.

Our results showed that SSZ-HAP-NPs clinically improved signs/symptoms more than SSZ, however, it was not statistically significant (P>0.05). Also, SSZ-HAP-NPs diminished histopathological evidence of injury, by decreasing inflammatory responses and balancing oxidative/anti-oxidative markers in colonic tissues (P>0.05). 

SSZ-HAP-NPs could be more effective than SSZ as standard drug in some laboratory and clinical signs/symptoms and side effects in colitis and this could be a good strategy for future studies to use nanoparticles with more anti-inflammatory effects to develop the efficiency of standard drugs in colitis treatment.