Comparing the efficacy in reducing brain injury of different neuroprotective agents following neonatal hypoxia–ischemia in newborn rats: a multi-drug randomized controlled screening trial

Abstract

Intrapartum hypoxia–ischemia leading to neonatal encephalopathy (NE) results in significant neonatal mortality and morbidity worldwide, with > 85% of cases occurring in low- and middle-income countries (LMIC). Therapeutic hypothermia (HT) is currently the only available safe and effective treatment of HIE in high-income countries (HIC); however, it has shown limited safety or efficacy in LMIC. Therefore, other therapies are urgently required. We aimed to compare the treatment effects of putative neuroprotective drug candidates following neonatal hypoxic-ischemic (HI) brain injury in an established P7 rat Vannucci model. We conducted the first multi-drug randomized controlled preclinical screening trial, investigating 25 potential therapeutic agents using a standardized experimental setting in which P7 rat pups were exposed to unilateral HI brain injury. The brains were analysed for unilateral hemispheric brain area loss after 7 days survival. Twenty animal experiments were performed. Eight of the 25 therapeutic agents significantly reduced brain area loss with the strongest treatment effect for Caffeine, Sonic Hedgehog Agonist (SAG) and Allopurinol, followed by Melatonin, Clemastine, ß-Hydroxybutyrate, Omegaven, and Iodide. The probability of efficacy was superior to that of HT for Caffeine, SAG, Allopurinol, Melatonin, Clemastine, ß-hydroxybutyrate, and Omegaven. We provide the results of the first systematic preclinical screening of potential neuroprotective treatments and present alternative single therapies that may be promising treatment options for HT in LMIC.

Early versus late caffeine and/or non‐steroidal anti‐inflammatory drugs (NSAIDS) for prevention of intermittent hypoxia‐induced neuroinflammation in the neonatal rat

“…Organ weight is one of the most sensitive indicators of drug toxicity and organ weight relative to body weight accounts for changes in overall body weight (Lazic et al, 2020), and may suggest an overall physiological response to the drug. Studies in animal models of HIE showed that Caff was protective against brain loss (Sabir et al, 2023). This was confirmed in our experiments which showed increased brain weight in the late hyperoxia and IH groups.…”

Synergistic effect of sildenafil combined with controlled hypothermia to alleviate microglial activation after neonatal hypoxia–ischemia in rats

“…In addition, in another mice model focal cerebral ischemia at P9, no significant difference in the brain volume lesions was also observed at 72 h after ischemia in animals exposed to Sildenafil whereas the treatment significantly reduced brain tissue loss 8 days after ischemia [ 21 ]. This observation is also relatively in line with a recent multi-drug randomized controlled screening trial in P7 Vannucci model [ 37 ] showing either a limited or the lack of effect of controlled hypothermia or Sildenafil respectively, when brain area loss is chosen as the primary outcome. Another difference among studies relates to the acute vs chronic exposure to Sildenafil.…”

Protocol to optimize the Rice-Vannucci rat pup model of perinatal asphyxia to ensure predictable hypoxic-ischemic cerebral lesions

“…Nevertheless, the RVM is notoriously prone to variability in terms of lesion size and severity and related functional deficits and to significant mortality of experimental animals (which itself can alter the accuracy of experimental populations). 3 , 7 , 8 , 9 , 10 , 11 , 12 Moreover, protocol modifications, often subtle, are usually described incompletely in publications, making comparisons among datasets difficult.…”