Potencial nefroprotetor dos ácidos ursólico e oleanólico na injúria renal aguda induzida pelo veneno da serpente Bothrops jararacussu

Abstract

The snakebite accident is considered a major public health problem, especially in tropical and subtropical countries. The consequences of these accidents result in sequelae like renal failure. Acute Kidney Injury (AKI) is a serious complication of Bothrops snakebite accidents, causing damage to the renal structure resulting from rhabdomyolysis, hemodynamic changes, immunological reactions and direct nephrotoxicity. Several strategies are studied in order to prevent AKI, such as the use of natural substances as part of the treatment. Among these substances, triterpenes are characterized by being bioactive secondary metabolites of plants with structural and functional varieties. Oleanolic acid and ursolic acid are characterized by their antioxidant and anti-inflammatory properties with nephroprotective effect. The present study aimed to investigate the effects of triterpenes on Bothrops jararacussu venom-induced AKI. First, we made the determination of intramuscular venom LD50 (10, 15, 20 and 40mg/Kg) by means of the probitus method, a regression that examines the relationship between two variables (venom dose X number of deaths). The result was a dose of 14.72 mg/kg. For the second experiment, the venom activity in vivo experiment, we chose to use 80% of the LD50 (11.77mg/Kg), to determine the best AKI timing. We divided mice in 10 groups (n = 6-8): a control group and a venom group at each time analyzed, 6, 12, 24, 72 and 96h of envenoming . Finished the analyzed times the animals were euthanized. The 6h and 12h group showed results compatible with AKI characterized by renal azotemia, reduced glomerular filtration rate and proteinuria. The 12h time was selected for the third stage, the treatment experiment with ursolic and oleanolic acids. In the treatment experiment, we divided mice into 6 groups (n = 6-8): control, triterpenes, venom, and venom + triterpenes at doses 25, 50 and 75 mg / kg. The animals received venom or saline at time 0, followed by treatment with saline or triterpenes in the 3rd and 9th hours, and were euthanized after 12 hours of envenoming. In the results found, the venom + triterpenes group at a dose of 75mg/Kg showed values suggestive of nephroprotective activity, with significance, in relation to the venom group, in the plasma creatinine ( VT75: 0,24 ± 0,03 mg/dL; V: 0,32 ± 0,04 mg/dL), plasma urea (VT75: 106,5 ± 36,73 mg/dL; V: 201,3 ± 25,22 mg/dL), plasma creatine kinase (VT75: 11434,0 ± 3639,0 U/L; V: 17737,0 ± 4245,0 U/L), urinary gamma-GT (VT75: 2,07 ± 0,58 U/mg de creat.; V: 4,09 ± 1,11 U/mg de creat.), renal TBARS (VT75: 1698,0 ± 196,0 nmol/mg of tissue; V: 2259,0 ± 636,6 nmol/mg of tissue). There was also a significant difference between the venom group and the control group in the gene expression of SOD1s (V: 0.62 ± 0.16; CTRL: 1.01 ± 0.17). The present study managed to reproduce the AKI model induced by a botropic envenoming. The 80% LD50 dose intramuscularly was able to cause renal and systemic damage characterized by loss of renal function and induction of oxidative process time dependent. The treatment with triterpenes managed to reduce the effects of AKI induced by B. jararacussu venom, being necessary other biomarkers analysis, besides SOD1s to prove the possible protection made by the antioxidant action of ursolic and oleanolic acids.