8-Iso-Prostaglandin F2α and Lipoxygenase Gene Expression as Candidate Molecular Markers of Training Adaptation in Professional Volleyball Players: A Pilot Study

Intensive training induces redox and inflammatory signaling that may facilitate adaptation but can also reflect excessive physiological strain. In this exploratory pilot longitudinal study, we assessed whether 8-iso-prostaglandin F2α (8-iso-PGF2α), a lipid peroxidation marker, and transcripts related to arachidonic acid lipoxygenase pathways change during a 10-week preparatory training period in elite female volleyball players. Twelve professional athletes were sampled at baseline after a training break and after training completion. 8-iso-PGF2α was quantified by gas chromatography–mass spectrometry (GC-MS), and the relative expression of arachidonate 5-lipoxygenase (ALOX5), arachidonate 12-lipoxygenase (ALOX12), and arachidonate 15-lipoxygenase (ALOX15) genes was measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in leukocytes and plasma-derived RNA. Training increased 8-iso-PGF2α from 0.06 [0.05–0.09] to 0.16 [0.08–0.22] ng/mL (p = 0.03). ALOX5 expression increased in leukocytes (0.80 ± 0.29 vs. 1.00 ± 0.29; p = 0.02) and plasma-derived RNA (0.03 [0.02–0.06] vs. 0.06 [0.05–0.11]; p = 0.04), whereas no statistically detectable pre-to-post changes were observed for ALOX12 and ALOX15 expression. Given the exploratory design and small sample size, these results should be interpreted as hypothesis-generating. The observed changes suggest that 8-iso-PGF2α and ALOX5 are associated with physiological responses to preparatory training and exercise-induced lipid oxidative remodeling; however, their potential utility for monitoring training adaptation requires validation in larger, prospectively designed controlled cohorts.