In Vivo Evaluation of Novel Anti-Inflammatory Agents

All rodents were housed at 25 °C in a 12/12 h light/dark cycle with access to food and water ad libitum. The procedures used in this study were fully approved by the Institutional Animal Care and Use Committee of the Intramural Research Program, National Institute on Aging, NIH (detailed in approved animal protocols 331-TGB-2024; 488-TGB-2022). Studies were performed in accord of the ARRIVE guidelines and recommendations, and all efforts were undertaken to minimize any potential animal suffering and as well as the number of animals used. This was achieved by incorporating the outcome measures from our prior studies [44 (link)] and a power analysis [45 (link)]. In this first-in-animal evaluation of TFBP and TFNBP in a rodent model of LPS-induced systemic and neuroinflammation and of TFBP in CCI TBI, studies were conducted in male rodents alone to evaluate whether these novel agents demonstrate a signal of in vivo anti-inflammatory efficacy using the least number of animals possible. This decision was made in the knowledge that gender differences have been identified in the response of rodents to TBI, in addition to other brain insults [46 (link)–48 (link)]. In this regard, TBI incidence in young to middle-aged adults is lower in women than men, and derives primarily from different causes [46 (link)]. More confusing in human studies is the effect of gender on TBI outcome. Considerably fewer studies have focused on women challenged with TBI in relation to males, and outcome varies in relation to age, menopausal status as well as severity of TBI and chosen outcome measure. Whereas human studies often report worse outcomes in women than men, importantly animal studies largely describe the opposite [46 (link)]. In this regard, studies in ovariectomized rodents have demonstrated that estrogens provide significant neuroprotection to mitigate damage in female rodents, but not necessarily in the human species [46 (link)]. Hence, to avoid potential confounds associated with estrogen generation in young female rodents, or potentially ovariectomizing animals or aging them to a postmenopausal state, we performed our first-in-animal studies, reported herein, in young adult male rodents. Aware that there are undoubtedly gender differences in relation to the pharmacokinetics, pharmacodynamics and tolerability of TFBP and TFNBP, these could then be evaluated in future studies in the event that a promising signal of efficacy is demonstrated in the first-in-animal investigation described herein.