Molecular Investigation of the Effects of Two Antiepileptic Drugs (Valproic Acid and Levetiracetam) on Alveolar Bone Under Orthodontic Force

<i>Background and Objectives:</i> This study aims to analyze the effects of levetiracetam (LEV) and valproic acid (VPA) administration on oxidative stress, inflammation, apoptosis, extracellular matrix dynamics, and bone remodeling parameters in rat alveolar bone exposed to orthodontic force. <i>Materials and Methods:</i> Four experimental groups were designed for this study: Control, Force, Force + LEV, and Force + VPA. LEV (150 mg/kg/day) or VPA (300 mg/kg/day) was administered intraperitoneally to the experimental groups daily for 6 weeks. At the end of the experimental period, the alveolar bone tissues were used for molecular analyses. RT-PCR analysis was performed to assess the expression levels of antioxidant markers [superoxide dismutase, (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH)], inflammatory cytokines [tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β)], apoptosis-related genes (Bax, Bcl-2, and Caspase-3), matrix remodeling genes [matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and metallopeptidase inhibitor 1 (TIMP-1)], and bone metabolism regulators [receptor activator of nuclear factor kappa-Β ligand (RANKL) and osteoprotegerin (OPG)]. Oxidative stress and inflammatory measurements were also confirmed via ELISA assays. <i>Results:</i> The results demonstrated that orthodontic force application increased oxidative stress, inflammation, and apoptosis compared to the Control group, disrupted extracellular matrix homeostasis, and increased bone resorption, while LEV administration (LEV + Force) markedly mitigated these abnormalities. In other words, LEV administration increased levels of antioxidant markers, decreased levels of inflammatory cytokines and pro-apoptotic genes, restored extracellular matrix balance (decrease in MMP-2 and MMP-9 with concurrent upregulation of TIMP-1), and limited tissue destruction (decrease in RANKL along with elevation in OPG). In contrast to LEV, VPA did not correct these molecular alterations induced by orthodontic force and, in several parameters, further exacerbated them. <i>Conclusions:</i> In conclusion, molecular data from the animal model indicate that LEV plays a protective role against orthodontic force by reducing excess levels of oxidative stress, apoptosis, and inflammation and homeostatic pathways.