Strain-Dependent Effects of Probiotic Supplementation on Heat Shock Protein Expression in Response to Exercise

Background Heat shock proteins (HSPs) play a central role in cellular homeostasis and stress adaptation during exercise. Among them, HSP60 is mainly associated with mitochondrial protein folding and metabolic adaptation, HSP70 is involved in general cytoprotection, and HSP90 is linked to stress-responsive signalling pathways[1], [2]. Probiotic supplementation may influence these molecular responses by modulation systemic inflammation, metabolic efficiency and exercise-related cellular stress. However, the effects of different probiotic strains on HSP expression remain poorly understood [3]. Objective/Aim Evaluate the effects of probiotic supplementation on HSP60, HSP70 and HSP90 expression following exercise, paying particular attention to the molecular response of different strains. The study examined the effects of two probiotic formulations: one containing both Lactobacillus and Bifidobacterium, and another containing only Lactobacillus, in order to evaluate the impact of different strains on the molecular response. Methods The same participants completed two separate 12-week probiotic supplementation phases, each based on different probiotic strains and separated by an interval period. Biological samples were collected before and after each intervention phase. The protein expression levels of HSP60, HSP70, and HSP90 were assessed using Western blot analysis. Pre- and post-supplementation profiles were compared to identify exercise-related and strain-dependent changes in heat shock protein expression. Results Probiotic supplementation has been associated with distinct changes in the expression of heat shock proteins. HSP70 levels remained essentially unchanged between the pre- and post-intervention assessments, which suggests that baseline cytoprotective activity was maintained. In contrast, HSP60 and HSP90 expression decreased following supplementation. The decrease in HSP90 may reflect a reduced need for stress-related signalling and the inflammatory response. Meanwhile, the reduction in HSP60 may indicate changes in adaptive mitochondrial signalling following probiotic intake. Overall, these results suggest that different probiotic strains may modulate the cellular stress response induced by exercise, shifting the molecular profile towards a less stress-responsive state. This effect was particularly evident in the formulation containing both Lactobacillus and Bifidobacterium, compared to the formulation containing only Lactobacillus. Conclusion Probiotic supplementation induced a selective modulation of heat shock protein expression following exercise. While HSP70 levels remained stable, HSP60 and HSP90 levels decreased after supplementation, indicating a differential effect on mitochondrial and stress-related pathways. These results confirm the strain-dependent role of probiotics in determining the molecular response to exercise and suggest their potential relevance in non-pharmacological strategies aimed at improving cellular adaptation and metabolic homeostasis. References [1] M. Sausa et al., “Lactobacillus fermentum LF31 Supplementation Reversed Atrophy Fibers in a Model of Myopathy Through the Modulation of IL-6, TNF-α, and Hsp60 Levels Enhancing Muscle Regeneration,” Nutrients , vol. 17, no. 9, 2025, doi: 10.3390/nu17091550. [2] E. G. Noble and G. X. Shen, “Impact of exercise and metabolic disorders on heat shock proteins and vascular inflammation,” 2012. doi: 10.1155/2012/836519. [3] H. Karlic, U. Krammer, and A. Haslberger, “Nutritional supplements for athletes and personalization; a short review,” 2022. doi: 10.31989/ffs.v2i10.993.