İnvestigation of 2- aminoethoxydiphenyl borate (2-APB)'s effects onaminoglycoside nephrotoxicity

Aminoglycosides are antibiotics that are effective on preventing Gram (-) infections and have been known and used for a long time. Despite of their advantages such as rapid and high antibacterial efficacy, low resistance development potential, synergistic effect with beta lactam antibiotics, and their low cost, clinical use of them is limited due to their side effects and especially because of high nephrotoxicity incidence. Although there are studies in the literature which used many different agents to improve aminoglycoside nephrotoxicity, there have been no study using 2- APB. This experimental study aims to investigate the protective effect of TRP channel modulator 2-APB on Gentamicin nephrotoxicity caused by ROS and calcium-induced apoptosis and inflammation which are the mechanisms in aminoglycoside nephrotoxicity. We aimed to evaluate the results by using light and electron microscopic, biochemical and immunohistochemical techniques. Forty Wistar rats were divided in 5 groups: Group 1: Control group (n=8): They did not receive anything. Group 2: DMSO group (n=8): %10 DMSO injected intraperitoneally (i.p.) once a day for 10 days. Group 3: 2- APB group (n=8): 2 mg/kg 2-APB dissolved in %10 DMSO injected intraperitoneally for 10 days. Group 4: Gentamicin group (n=8): 100 mg/kg Gentamicin injected intramuscularly for 10 days. Group 5: Gentamicin+ 2-APB group (n=8): 100 mg/kg Gentamicin injected intramuscularly for 10 days. 30 minutes before gentamicin injection, 2 mg/kg 2- APB applied intraperitoneally. After sacrification, blood samples collected for biochemical investigation, kidney tissue samples collected for light and electron microscopic and immunohistochemical investigation. Glomerular degeneration, tubular dilatation, vacuolization, desquamation of tubular cells and hyaline cast formation in luminal space and leukocyte infiltration were seen in kidneys of the rats in Gentamicin group under light microscopic examination. In electron microscopic observation; occasional glomerular basement membrane thickening, disorganization of microvillus of tubular cells, apical cytoplasmic blebbing, lipid accumulation, myelin figure like structure formation, an increase in the amount of lysosome, mitochondrial swelling and disorganization of cristae structure, apoptotic changes and widening of intercellular space were found. It was observed that Tumor Necrosis Factor alpha (TNF-α), İnterleukin 6 (IL-6) and caspase 3 expressions were increased in kidney tissues of gentamicin group. It was remarkable that there was an increasing in BUN and creatinine levels which are used for evaluating kidney functions. Also it was determined that there were an increase in MDA levels as an indicator of lipid peroxidation and decrease in levels of SOD which is an antioxidant. Even though degeneration still continues in Gentamicin+2ABP treatment group, it was observed that the severity and the area it occupied decreased and the glomerular and tubule structures were generally preserved. In Gentamicin+ 2-APB treatment group TNF-α, IL-6, caspase 3 immunoreactivity and BUN, creatinin, MDA levels reduced and SOD levels increased markedly when compared with Gentamicin group. In conclusion, it has been considered that 2-APB can prevent Gentamicin mediated nephrotoxicity with its anti-oxidant, anti-apoptotic and anti-inflammatory effects.