Evaluation of Early and Delayed Meloxicam Treatment Against Regulated Cell Death Pathways and ERK1/2 Phosphorylation in a Rat Model of Renal Ischemia–Reperfusion Injury

Objectives: Renal ischemia–reperfusion (I/R) injury is one of the most important pathological triggers of acute kidney injury. This study aimed to investigate the protective effects of meloxicam, a selective cyclooxygenase-2 (COX-2) inhibitor, against renal I/R injury through specific cell death pathways including inflammation, apoptosis, necroptosis, and the MAPK/ERK pathway, which is potentially linked to regulated cell death mechanisms such as ferroptosis. Methods: Male Wistar Albino rats weighing 280–300 g were used in the study and were divided into four groups: Sham, IR (40 min ischemia + 120 min reperfusion), Meloxicam + IR, and Meloxicam + IR1. Bilateral renal ischemia was induced for 40 min via a retroperitoneal approach under anesthesia. Meloxicam was administered intravenously at a dose of 1 mg/kg at the initiation of reperfusion in the Meloxicam + IR group, whereas in the Meloxicam + IR1 group, the same dose was administered 1 h after the onset of reperfusion. Total reperfusion time was 120 min in both groups. Renal function parameters (BUN and creatinine) and oxidative stress markers (TAS and TOS) were measured. Inflammatory cytokines (IL-6, IL-1β, and IL-10), the glomerular filtration injury marker Cystatin C, the tubular injury marker KIM-1, the apoptotic marker Caspase 3, the necroptosis markers RIPK3 and MLKL, and MAPK signaling pathway alterations (ERK1/2 and pERK1/2 levels) associated with cellular survival and death signaling were evaluated. Results: Most notably, meloxicam markedly modulated apoptosis, the expression of necroptosis markers RIPK3 and MLKL, and the activation of pERK1/2, a key node in MAPK signaling that is regulatory in cell survival and cell death processes. The drug also suppressed pro-inflammatory cytokines (IL-6 and IL-1β) while preserving anti-inflammatory IL-10 levels. Furthermore, improvements were observed in the levels of KIM-1, a marker of tubular injury, and Cystatin C, a marker of glomerular filtration impairment. Consequently, meloxicam administration significantly reduced the elevated serum creatinine and TOS levels observed in the IR group, although serum BUN levels remained without notable alteration. Conclusions: The findings of this study suggest that meloxicam may extend beyond its role as a classical anti-inflammatory agent, potentially offering biochemical and functional protection against renal I/R injury in association with the modulation of specific cell death mechanisms, including necroptosis and apoptosis, as well as the MAPK signaling pathway.