Ambroxol, a mucolytic agent, boosts HO-1, suppresses NF-κB, and decreases the susceptibility of the inflamed rat colon to apoptosis: A new treatment option for treating ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease of unknown etiology that increases the risk of developing colorectal cancer and imposes a lifelong healthcare burden on millions of patients worldwide. Current treatment strategies are associated with significant risks and have been shown to be fairly effective. Hence, discovering new therapies that have better efficacy and safety profiles than currently exploited therapeutic strategies is challenging. It has been well delineated that NF-κB/Nrf2 crosstalk is a chief player in the interplay between oxidative stress and inflammation. Ambroxol hydrochloride, a mucolytic agent, has shown antioxidant and anti-inflammatory activity in humans and animals and has not yet been examined for the management of UC. Therefore, our approach was to investigate whether ambroxol could be effective to combat UC using the common acetic acid rat model. Interestingly, a high dose of oral ambroxol (200 mg/kg/day) reasonably improved the microscopic and macroscopic features of the injured colon. This was linked to low disease activity and a reduction in the colonic weight/length ratio. In the context of that, ambroxol boosted Nrf2 activity and upregulated HO-1 and catalase to augment the antioxidant defense against oxidative damage. Besides, ambroxol inactivated NF-κB signaling and its consequent target pro-inflammatory mediators, IL-6 and TNF-α. In contrast, IL-10 is upregulated. Consistent with these results, myeloperoxidase activity is suppressed. Moreover, ambroxol decreased the susceptibility of the injured colon to apoptosis. To conclude, our findings highlight the potential application of ambroxol to modify the progression of UC by its anti-inflammatory, antioxidant, and antiapoptotic properties.