Assessment of the Toxicity of Hydralazine in the Rat Using an Ultrasensitive Flow-based Cardiac Troponin I Immunoassay

Abstract

The purpose of this study was to correlate the histologic changes in the heart to serum cardiac troponin I (cTnI) concentrations assayed with the Erenna Immunoassay System in Wistar rats (Crl:Wi[Han]) using the hydralazine model of cardiotoxicity. A single dose of hydralazine caused an increase of cTnI concentrations at six hours post-dose, followed by a sharp decrease at twenty-four hours and a return to baseline at fortyeight hours. The second dose of hydralazine caused a smaller magnitude increase in cTnI concentrations at six hours as compared to the first dose. Also, cTnI concentrations returned to baseline at twenty-four hours after the second dose. The increased cTnI concentrations coincided with acute myocardial necrosis at histology. However, increased cTnI concentrations in the absence of microscopic lesions were identified in several rats. As cTnI concentrations decreased, microscopic changes in the heart matured to cardiomyophagy. In conclusion, the increases in cTnI concentrations six hours after the administration of hydralazine were indicative of a myocardial damage that did not consistently have a microscopic correlate. However, the window of increased cTnI concentrations was short, and only microscopic evaluation of the heart detected the damage at twenty-four to fortyeight hours after the episode of acute myocardial necrosis.

Therapeutic Effects of Hydralazine on Renal Ischemia-Reperfusion Injury in Rat.

“…The study groups included: (1) control group: did not receive the drug; (2) sham group: under anesthesia, only the kidneys were exposed without any ischemia; (3) I-R group: bilateral renal artery and vein occlusion for 20 min; then with 24 h reperfusion; (4) hydralazine treatment group: bilateral renal artery and vein occlusion for 20 min and then hydralazine(5 mg/kg, NOVAPLUS, USA) + 24 ho immediately after reperfusion initiation. [9][10][11] To induce AKI, the animals were weighed first and then sodium thiopental (25 mg/kg; Sandoz, GmbH, Estonia) was injected intraperitoneally into the animal, 12 and after shaving the back hair, 1.5 cm incisions were made on either side of the midline using scissors and forceps. The artery and vein of both kidneys were blocked using a special clamp for 30 min, instantly after the end of the period, the obstruction was removed and the surgical area sutured with silk thread 3-0 and the animals were kept in a separate cage for recovery.…”

“…7 HIF-1 can increase NO production by multiple mechanisms, including increasing the expression of iNOS and COX4-2. 8 Considering the characteristics of hydralazine in releasing endogenous NO 9,10 ; in this study, we aim to investigate the effects of hydralazine post-treatment administration on renal injury caused by I-R.…”

Cardiac troponins—Translational biomarkers in cardiology: Theory and practice of cardiac troponin high‐sensitivity assays

“…Now we can show on the proteomic data that it can be attributed to the use of a capture antibody (aa 87-91) for an epitope with only 60% homology for rodent but 100% for dog. cTnI concentrations in preclinical studies have also been measured via the Beckman Coulter Access 2 platform, which has a lower limit of detection (LoQ) of 30 pg/mL in the rat [12]. These assays have enabled cTnI concentration measurements in rat serum after severe acute cardiac insult; however, the sensitivity BioFactors is insufficient for accurate measurements of cTnI concentrations in healthy animals or in animals after discrete cardiac injury.…”

“…In addition to commercially available immunoassays for human cTn, several companies produce ELISA kits that are designed specifically for individual species such as rat, mouse, and dog. Moreover, the range of biomarkers of cardiac injury was revolutionized by introducing the highly sensitive cTn assays, which are of particular importance for cardiotoxic studies involving mild-to-moderate myocardial injury [12][13][14]. In addition, due to the development of new technologies enabling multiplexing (e.g., Luminex), cardiac troponins have become an important part of multimarker panels, which provide complex information on the pathological processes underlying various forms of cardiovascular diseases [15].…”

Differential analysis of transient increases of serum cTnI in response to handling in rats

“…Until recently, baseline serum concentrations in healthy humans and animals were below the lower limits of detection (LLoD) and quantification (LLoQ) of available assays (Todd et al 2007 ). With the advent of ultrasensitive cTnI and cTnT assays with LLoD and LLoQ in the sub-picogram/mL range, serum cTn concentration reference ranges have been identified in multiple species (Todd et al 2007 ; Schultze et al 2008 , 2009 ; Mikaelian et al 2009 ; Herman et al 2011 ). The mean serum cTnI concentration is below 10 pg/mL in healthy naïve Wistar, WKY and Sprague-Dawley rats, and ∼18 pg/mL in healthy naïve Fisher rats (Herman et al 2011 ).…”