Synbiotic Supplementation of Lactobacillus sp. and Bifidobacterium sp. Modulates Serum GABA/Glutamate Ratio in a Pentylenetetrazole-Induced Epileptic Rat Model

Epilepsy is a chronic neurological disorder characterized by recurrent seizures resulting from an imbalance of neurotransmitters between inhibitory gamma-aminobutyric acid (GABA) and excitatory (glutamate). The GABA/glutamate ratio plays a crucial role in the pathogenesis of epilepsy. This study evaluated the effects of synbiotic supplementation containing Lactobacillus sp. and Bifidobacterium sp. on serum levels of GABA, glutamate, and GABA/glutamate ratio in pentylenetetrazole (PTZ)-induced rat model of epilepsy. Forty male Wistar rats were randomized to five groups: (K−, K+, P1 valproic acid, P2 synbiotic, P3 synbiotic and valproic acid). Serum GABA and glutamate were measured by enzyme-linked immunosorbent assay (ELISA) and analyzed using Shapiro–Wilk, one-way ANOVA with post hoc Tukey HSD (glutamate), and Kruskal–Wallis with pairwise Mann–Whitney (GABA and GABA/glutamate ratio), with α = 0.05. GABA levels did not differ among groups (p = 0.173). Glutamate levels differed significantly among groups (p = 0.015) and differed significantly in P3 compared with K+ (p = 0.027). The GABA/Glutamate ratio showed an overall group effect (p = 0.013), with significant differences only in the P3 with K+ comparisons (p = 0.016). Notably, the combination of a synbiotic and valproic acid significantly reduced glutamate concentrations and increased the GABA/glutamate ratio. However, they were not statistically significant for GABA levels. The findings may depend on the probiotic/prebiotic composition, as well as the treatment duration.