Toxicity of Water Contaminated with Nitrate on the Guinea Pigs Treated with Cimetidin

Abstract

Background: The reduction of nitrate (NO3-) to toxic nitrite (NO2-) via bacterial enzymes is highly dependent on gastric pH. At specific medical conditions such as hypochlorhydria or achlorhydria (less acidic, high gastric pH), there is a significant risk of bacterial overgrowth that contributed to increase the conversion of nitrate to the nitrite in the stomach. Young monogastric animals (alike to human infants) are more sensitive to nitrate toxicity due to high gastric pH. Aims: This study aimed to evaluate the toxicity of nitrate under higher gastric pH condition following cimetidin treatment. Moreover, it used Guinea pigs as a surrogated model for monogastric digestive system to assess nitrate toxicity under specific gastric medical problems. Results: The administration of 50 mg/kg.bw of cimetidin leads to an increase in stomach pH in Guinea pig as monogastric model following 6 weeks of the experimental period. The severity of the histopathological changes of stained stomach, liver, kidney, spleen and lung sections were higher in G2 (potassium nitrate + cimetidin-treated Guinea pigs) than in G3 (nitrate-toxicated Guinea pigs). Conclusions: Under high gastric pH, the pathological changes were significantly higher in G2 (nitrate and cimetidin-treated group) than in the other groups. Furthermore, Guinea pigs represented a valuable monogastric surrogate model for both human and small animals to assess nitrate toxicity under specific gastric medical problems.