Effects of N-acetyl-L-cysteine on redox status and markers of renal function in mice inoculated with Bothrops jararaca and Crotalus durissus terrificus venoms.

Renal dysfunction is an important aggravating factor in accidents caused by Crotalus durissus terrificus (Cdt) and Bothrops jararaca (Bj) bites. N-acetyl-l-cysteine (NAC) is well known as a nephroprotective antioxidant with low toxicity. The present study investigated the effects of NAC on redox status and markers of renal function in mice that received vehicle (controls) or venoms (v) of Cdt and Bj. In controls NAC promoted hypercreatinemia, hypouremia, hyperosmolality with decreased urea in urine, hyperproteinuria, decreased protein and increased dipeptidyl peptidase IV (DPPIV) in membrane-bound fraction (MF) from renal cortex (RC) and medulla (RM). NAC ameliorated or normalized altered creatinuria, proteinemia and aminopeptidase (AP) acid in MF, AP basic (APB) in soluble fraction (SF), and neutral AP in SF and MF from RC and RM in vBj envenomation. NAC ameliorated or normalized altered neutral AP in SF from RC and RM, and DPPIV and protein in MF from RC in vCdt envenomation. NAC ameliorated or restored renal redox status respectively in vCdt and vBj, and normalized uricemia in both envenomations. These data are promising perspectives that recommend the clinical evaluation of NAC as potential coadjuvant in the anti venom serotherapy for accidents with these snake's genera.

Differential efficiency of simvastatin and lipoic acid treatments on Bothrops jararaca envenomation-induced acute kidney injury in mice.

Snake bite accidents by Bothrops genus is an important public health issue in Brazil and one of its most serious complications is the acute kidney injury (AKI). Here we evaluated the effects of Bothrops jararaca venom (vBj) and the treatments with lipoic acid (LA) and simvastatin (SA) on renal function, aminopeptidase (AP) activities and renal redox status. Primordial events for establishment of AKI by vBj were hyperuricemia, hypercreatinemia, urinary hyperosmolality, renal oxidative stress and reduction of hematocrit and protein content in the membrane of renal cortex and medulla and in the plasma. In the renal cortex and medulla the changes caused by vBj in soluble and membrane-bound AP activities had a similar pattern. The beneficial effects of LA and SA on envenomed mice were similar on the hyperuricemia, renal oxidative stress and reduction of hematocrit. LA mitigated the hypercreatinemia, but exacerbated the urinary urea and creatinine, whereas SA mitigated the decrease of plasma urea, urinary hyperosmolality and hypercreatinuria induced by vBj. The beneficial effects of LA and especially of SA on renal effects of vBj open a new perspective for clinical investigations of these drugs as coadjuvant agents in the serotherapy of Bothrops envenomation.

Dipeptidyl peptidase IV in the hypothalamus and hippocampus of monosodium glutamate obese and food-deprived rats.

Proline-specific dipeptidyl peptidases are emerging as a protease family with important roles in the regulation of signaling by peptide hormones related to energy balance. The treatment of neonatal rats with monosodium glutamate (MSG) is known to produce a selective damage on the arcuate nucleus with development of obesity. This study investigates the relationship among dipeptidyl peptidase IV (DPPIV) hydrolyzing activity, CD26 protein, fasting, and MSG model of obesity in 2 areas of the central nervous system. Dipeptidyl peptidase IV and CD26 were, respectively, evaluated by fluorometry, and enzyme-linked immunosorbent assay and reverse transcriptase polymerase chain reaction in soluble (SF) and membrane-bound (MF) fractions from the hypothalamus and hippocampus of MSG-treated and normal rats, submitted or not to food deprivation (FD). Dipeptidyl peptidase IV in both areas was distinguished kinetically as insensitive (DI) and sensitive (DS) to diprotin A. Compared with the controls, MSG and/or FD decreased the activity of DPPIV-DI in the SF and MF from the hypothalamus, as well as the activity of DPPIV-DS in the SF from the hypothalamus and in the MF from the hippocampus. Monosodium glutamate and/or FD increased the activity of DPPIV-DI in the MF from the hippocampus. The monoclonal protein expression of membrane CD26 by enzyme-linked immunosorbent assay decreased in the hypothalamus and increased in the hippocampus of MSG and/or FD relative to the controls. The existence of DPPIV-like activity with different sensitivities to diprotin A and the identity of insensitive with CD26 were demonstrated for the first time in the central nervous system. Data also demonstrated the involvement of DPPIV-DI/CD26 hydrolyzing activity in the energy balance probably through the regulation of neuropeptide Y and ß-endorphin levels in the hypothalamus and hippocampus.

Dipeptidyl peptidase IV in the hypothalamus and hippocampus of monosodium glutamate obese and food-deprived rats

Proline-specific dipeptidyl peptidases are emerging as a protease family with important roles in the regulation of signaling by peptide hormones related to energy balance. The treatment of neonatal rats with monosodium glutamate (MSG) is known to produce a selective damage on the arcuate nucleus with development of obesity. This study investigates the relationship among dipeptidyl peptidase IV (DPPIV) hydrolyzing activity, CD26 protein, fasting, and MSG model of obesity in 2 areas of the central nervous system. Dipeptidyl peptidase IV and CD26 were, respectively, evaluated by fluorometry, and enzyme-linked immunosorbent assay and reverse transcriptase polymerase chain reaction in soluble (SF) and membrane-bound (MF) fractions from the hypothalamus and hippocampus of MSG-treated and normal rats, submitted or not to food deprivation (FD). Dipeptidyl peptidase IV in both areas was distinguished kinetically as insensitive (DI) and sensitive (DS) to diprotin A. Compared with the controls, MSG and/or FD decreased the activity of DPPIV-DI in the SF and MF from the hypothalamus, as well as the activity of DPPIV-DS in the SF from the hypothalamus and in the MF from the hippocampus. Monosodium glutamate and/or FD increased the activity of DPPIV-DI in the MF from the hippocampus. The monoclonal protein expression of membrane CD26 by enzyme-linked immunosorbent assay decreased in the hypothalamus and increased in the hippocampus of MSG and/or FD relative to the controls. The existence of DPPIV-like activity with different sensitivities to diprotin A and the identity of insensitive with CD26 were demonstrated for the first time in the central nervous system. Data also demonstrated the involvement of DPPIV-DI/CD26 hydrolyzing activity in the energy balance probably through the regulation of neuropeptide Y and â-endorphin levels in the hypothalamus and hippocampus.

Lipoic acid effects on renal function, aminopeptidase activities and oxidative stress in Crotalus durissus terrificus envenomation in mice.

Crotalus durissus terrificus envenomation has been associated with direct nephrotoxicity, rhabdomyolysis, hyperuricemia, urinary hypoosmolality, alterations in aminopeptidase activities (AP) and oxidative stress. This study evaluated the effects of lipoic acid (LA) on renal function, lethality, AP and GSSG/GSH in mice injected with C. d. terrificus venom (vCdt). The doses and routes of administration of LA and vCdt promoted no systemic myotoxicity. LA did not alter significantly the lethality of vCdt. In nonenvenomed, LA induced hypercreatinemia, urinary hyperosmolality, decrease of urinary urea and creatinine, increase of protein in plasma and in soluble fraction (SF) and decrease in membrane-bound fraction (MF) of cortex and medulla. Decreased levels of all AP (except neutral-AP in MF-medulla) were also induced by LA in nonenvenomed. LA associated with vCdt decreased plasma osmolality, hematocrit, urinary uric acid, but increased urinary and SF-medullar protein. LA mitigated the increase of protein in SF-cortex and corrected hyperuricemia, GSSG/GSH and protein in MF-cortex and MF-medulla, as well as decreased plasma neutral AP and acid AP in MF-medulla of envenomed mice. Data suggest that LA contributes to the solubilization/remotion of proteins in MF with impairment of most AP, but it could be beneficial for the treatment of the direct nephrotoxicity of vCdt.

Lipoic acid effects on renal function, aminopeptidase activities andoxidative stress in Crotalus durissus terrificus envenomation in mice

Crotalus durissus terrificus envenomation has been associated with direct nephrotoxicity, rhabdomyolysis, hyperuricemia, urinary hypoosmolality, alterations in aminopeptidaseactivities (AP) and oxidative stress. This study evaluated the effects of lipoic acid (LA) on renal function, lethality, AP and GSSG/GSH in mice injected with C. d. terrificus venom (vCdt). The doses and routes of administration of LA and vCdt promoted no systemic myotoxicity. LA did not alter significantly the lethality of vCdt. In nonenvenomed, LA induced hypercreatinemia, urinary hyperosmolality, decrease of urinary urea and creatinine, increase of protein in plasma and in soluble fraction (SF) and decrease in membraneboundfraction (MF) of cortex and medulla. Decreased levels of all AP (except neutral-AP in MF-medulla) were also induced by LA in nonenvenomed. LA associated with vCdt decreased plasma osmolality, hematocrit, urinary uric acid, but increased urinary and SF-medullar protein. LA mitigated the increase of protein in SF-cortex and corrected hyperuricemia, GSSG/GSH and protein in MF-cortex and MF-medulla, as well as decreased plasma neutral AP and acid AP in MF-medulla of envenomed mice. Data suggest that LA contributes to the solubilization/remotion of proteins in MF with impairment of most AP,but it could be beneficial for the treatment of the direct nephrotoxicity of vCdt.

Aminopeptidase activities, oxidative stress and renal function in Crotalus durissus terrificus envenomation in mice.

Acute renal failure is a serious condition of Crotalus bites, which could be treated with statins. The effects of Crotalus durissus terrificus venom (vCdt) and simvastatin on renal function, oxidative stress and representative plasma, urinary and renal aminopeptidase (AP) activities were evaluated in mice. Eighty percent LD50 of vCdt caused hyperuricemia and urinary hypoosmolality (100%) and hypercreatinemia (60%). Plasma neutral, pyroglutamyl and dipeptidyl IV and renal soluble and membrane-bound APs were susceptible to vCdt. Cortical and medullar oxidative stress (GSSG/GSH ratio) was increased by vCdt. Simvastatin (3mg/kg body wt.) altered urinary creatinine and urea, membranal protein in cortex and medulla, plasma neutral and dipeptidyl IV APs and most of renal APs in nonenvenomed, and exacerbated hypercreatinemia, but mitigated uricosuria, renal oxidative stress and protein increase in envenomed. Hyperuricemia and urinary hypoosmolality are early signs of indirect myotoxicity of vCdt with diagnostic significance. In kidney, oxidative stress and alteration of protein content and AP activities suggest membrane destruction, enzyme release and protein loss, which may be due to direct tissue damage. Plasma AP activities might be nephrotoxicity markers of C. d. terrificus envenomation. The deleterious effects of simvastatin on creatinemia and APs constitute important restrictions to its use within the antivenom therapy.