Antioxidative action of manganese treatment in delayed healing of acetic acid-induced ulceration in rat stomach

Background: The role of manganese in disease treatment such as diabetes, arthritis and osteoporosis has been well documented. Unhealed or delayed gastric ulcer is an experimental model mimicking recurrent peptic ulcer of which information is lacking. This study sought to examine the role of manganese during delayed gastric ulcer healing and its probable mechanism. Methods: 75 male wistar rats (150-170g) were divided into 5 groups of 15 rats each; Groups 1 was delayed untreated ulcerated animals while II, III, IV and V received 100mg/kg Manganese, 50mg/kg Manganese, 40 mg/kg Cimetidine and 100mg/kg Vitamin E respectively. Ulcer was induced by serosa application of 30% acetic acid and by day 5 post-induction, ulcer was delayed by continuous subcutaneous administration of 2mg/kg indomethacin (once daily) for 14 days simultaneously. Body weights of experimental animals were monitored daily, haematological studies; stomach ulcer score, biochemical and histological analysis were assessed by days 3, 7 and 14 indomethacin and drug treatment after quick decapitation. Data were expressed as Mean + SEM, analysed using one-way ANOVA while p=0.05 was considered statistically significant. Results: The percentage healing rates in Manganese (50mg/kg and 100mg/kg respectively) significantly increased on days 3 (76.5% and 42.9%), 7 (97.3% and 75.5%) and 14 (100% and 97.5%). Haematological data revealed increased circulating blood cells in the Manganese and Vitamin E treated groups compared with ulcerated untreated groups. Manganese treatment reduced gastric inflammation and lipid peroxidation (malodiadehyde, MDA) with a concomitant increase in superoxide dismutase and nitric oxide levels of gastric tissue homogenate compared with other treatment groups. Histological evaluations of gastric tissue from the manganese treated groups revealed healing compared with other treatment groups which further buttressed biochemical analysis. Conclusion: Manganese probably exerts its gastro-protective property on delayed ulcer by promoting increased antioxidant levels in experimental animals which probably mitigated the effect of continuous indomethacin injection.Keywords: Manganese, delayed ulcers, anti-inflammatory and antioxidative activitie