Comparative study of sodium bicarbonate- and magnesium hydroxide-based gastric antacids for the effectiveness of Salmonella delivered Brucella antigens against wild type challenge in BALB/c mice

Abstract

We compared the effects of two antacid formulations based on sodium bicarbonate and magnesium hydroxide on a Salmonella-delivered oral Brucella live attenuated vaccine. We conducted a series of in vitro and in vivo experiments to investigate the pH buffering capacity, buffering longevity, and the effects of these formulations on the survival of Salmonella under neutralized pH conditions and its impact on immune responses. Magnesium hydroxide had a greater, stable, and prolonged buffering capacity than sodium bicarbonate and was safer when administered orally. Oral administration of sodium bicarbonate resulted in discomfort as reflected by mouse behavior and mild muscle tremors, whereas mice treated with magnesium hydroxide and PBS were completely normal. Gastric survival studies using BALB/c mice revealed that a higher number of Salmonella reached the intestine when the magnesium hydroxide-based antacid buffer was administrated. Co-administration with attenuated Salmonella secreting Brucella antigens, SodC, and Omp19 along with individual antacid formulations, significantly enhanced the antigen-specific protective immune responses against virulent Brucella challenge. Together, our results indicated that the pre vaccinated oral administration of bicarbonate-citric acid or magnesium hydroxide-based neutralizing buffers significantly counteract stomach acidity by maintaining the viability of an oral enteric vaccine formulation.

Breaking Osteoclast‐Acid Vicious Cycle to Rescue Osteoporosis via an Acid Responsive Organic Framework‐Based Neutralizing and Gene Editing Platform

“…Furthermore, systemic delivery of NaHCO 3 is not an ideal approach since it will affect the acidic condition in the stomach or mild muscle tremors. [ 66 ] Therefore, the role of local injection would be applied more reasonable, which can be combined with other orthopedic material modifications in the future, such as surface modification of steel plates and application of bone cement to treat the fractures under osteoporotic status. Excitedly, this composite nanomaterial unsurprisingly shows promising results in reversing bone loss in OVX mice.…”