Effect of two partition from the leaves of Byrsonima intermedia in the model of gastric ischemia-reperfusion injury in rats

RC Santos1, M Sannomyia2, C M Rodrigues3, W Vilegas3, L R M Rocha1, C A Hiruma-Lima0. 1Biosciences Institute of Botucatu, , Department of Physiology, Brazil, 2School of Arts, Sciences and Humanities, School of Arts, Sciences and Humanities, Brazil, 3Chemistry Institute, Department of Organic Chemistry, Brazil

Introduction: B. intermedia (BI), a small murici, is a Cerrado bush considered as medicinal due to its astringent property in diarrheas, dysenteries and antiulcerogenic actions. The present work aimed to evaluate the mechanism of action of two partitions aqueous (AcoAq) and acetate (AcoEt) obtained from the leaves of BI in ischemia-reperfusion model in the rat stomachs. Materials and Methods: Male Wistar rats (180-220 g) were separated into four groups (n = 7-9): negative control (vehicle) positive control (30mg/kg lansoprazole), AcoAq group and AcoEt (100 mg/kg), all treatments were administered orally. The animals were anesthetized, (ketamine and xylazine 0.8 and 0.4 mg/kg, respectively, by intramuscular route), and the evaluation was made in two different procedures: pretreatment 30 minutes before the ischemia-reperfusion injury followed or treatment with 6 days after the surgery. In order to analyze the activity of the partitions, the level of total glutathione (GSH – nmol/g of tissue), myeloperoxidase (MPO – unit of Myeloperoxidase/g of tissue) and cytokines IL-1b, IL-10 and TNF-a (pg/mL) were measured. The lesion area (mm2) was quantified with AVSoft® program image. The results were expressed as mean ± mean standard error of parameters obtained. The statistical analyses adopted were ANOVA followed by Dunnett\'s test. Results and discussion: The prior treatment with partitions AcoAq and AcoEt significantly reduced (p<0.05) the area of ​​injury caused by ischemia reperfusion in 27.0±5.5 and 21.1±5.7 respectively when compared to vehicle (113.8±28.4). In the MPO quantification it was possible to observe that there was a reduction (274.2±22.9 and 225.2±9.3, respectively) when compared to vehicle (410±59.1). After that, we choose to perform the procedure of ischemia-reperfusion followed by treatment for 6 consecutive days after surgery. As result, it was possible to observe that only AcoEt reduced the lesion area (45.6±10.1) compared to vehicle (103.9±9.9). Then, the levels of GSH were evaluated which showed an increase (1282.0±145.3) when compared with vehicle (682.7±23.6) for this partition . It was also observed a significant decrease in the level of MPO (334.3±26.6) and increse in the level of IL-10 (7409.0 ± 568.6),when compared to vehicle (613.8±35.7 and 3651 ± 207.3, respectively . The levels of TNF-a and IL-1B were reduced in the gastric mucosa (286.4±47.3 and 501.6 ± 48.6, respectively) when compared to vehicle group (566.1±62.7 and 993.5±94.6), demonstrating that while reducing the area of injury, AcoEt also significantly reduced major proinflammatory cytokines. Conclusion: Both pre-treatment with AcoEt AcoAq prevented the formation of lesions caused by ischemia-reperfusion, by reducing the level of MPO. However, after the establishment of tissue damage, only the partition AcoEt was able to reduce the lesion area, it decreases parameters proinflammatory (IL-1b and TNF-a) whereas the level of IL-10 (cytokine anti-inflammatory) was maintained. AcoEt partition presents mainly flavonoids in its constitution, possibly, these are compounds responsible for this activity in the gastric mucosa to prevent the formation of gastric lesions and AcoEt also reduce them after its implementation by ischemic-reperfusion.

Financial Support: BIOTA/FAPESP process 2009/54761-7