Preservation of Antioxidant and Immunomodulatory Properties in a Heat-Treated Probiotic Blend: Insights from Preclinical Models

In a previous clinical trial, it was shown that a probiotic blend (Bifidobacterium longum CECT 7347 (Esflorin1™), Lacticaseibacillus rhamnosus CECT 8361 (BPL15) and Lacticaseibacillus casei CECT 9104 (BPL4)) reduced oxidative stress in males engaging in intense exercise. The present study evaluated whether the probiotic blend’s functional properties are preserved after heat treatment and investigated the underlying mechanism of action using preclinical models. The antioxidant, immunomodulatory and intestinal effects of the heat-treated and probiotic blends were assed using in vitro assays and Caenorhabditis elegans (C. elegans) models. The heat-treated blend preserved the antioxidant activity by scavenging free radicals, reducing intracellular reactive oxygen species and enhancing survival in C. elegans under oxidative stress, possibly via sod-3 upregulation in the CF1553 strain. It also enhanced mitochondrial biogenesis and ATP production in C2C12 via AMPK phosphorylation. Both versions attenuated a gut inflammatory response, improved intestinal barrier in Caco-2 cells and C. elegans and exhibited immunomodulatory activity in U937 macrophages at the tested concentrations. These findings support the heat-treated blend as a promising postbiotic supplement to manage oxidative stress and other physiological alterations associated with intense exercise.