The Potential Mechanism of Histamine-Inducing Cardiopulmonary Inflammation and Apoptosis in a Novel Oral Model of Rat Intoxication

Histamine (HIS) is a potent vasodilator that contributes to anaphylactic reactions. Our investigation aims to study the possible toxic impact of repeated oral administration of histamine on the target organs of HIS poisoning (lung & heart) in rats as a model of scombroid poisoning. We used 15 rats that were separated into three groups with 5 rats in each. All rats received the treatments orally for 14 days as follows; (1): distilled water, (2) HIS at a dosage level of 250 mg/kg BWT daily and (3) HIS at a dosage level of 1750 mg/kg BWT weekly. Our results revealed that the consumption of HIS either daily or weekly could cause marked cardiopulmonary toxicity in rats. HIS can trigger inflammatory reactions in the cardiopulmonary tissues and induce oxidative stress damage along with apoptosis of such organs. HIS was markedly increase the MDA levels and decrease the CAT and GSH activity in both lung and heart tissues. The main pathological lesion observed is inflammation which was confirmed by immunohistochemistry and demonstrated strong iNOS and TNF-α protein expressions. Cardiac muscles showed extensive degeneration and necrosis and displayed strong casp-3 protein expression. Additionally, all HIS receiving groups noticed marked elevation of the pulmonary transcription levels of Cox2, TNF-α, and IL1β along with substantial elevation of casp-3 and bax genes and downregulation of Bcl2 gene in the cardiac tissue. We concluded that the oral administration of HIS either daily or weekly can induce cardiopulmonary toxicity via the upregulation of proinflammatory cytokines resulting in ROS overgeneration and inducing both oxidative stress and apoptosis.