Multivariate Temporal Inflammatory–Regenerative Signatures of Bovine Platelet-Rich Gel Supernatants Under Different Storage Temperatures

Platelet-rich gel supernatants (PRGS) are increasingly used in veterinary medicine due to their regenerative and immunomodulatory properties; however, most studies focus on individual mediators and provide limited insight into their coordinated biological behavior. This study aimed to characterize the integrated inflammatory–regenerative signatures of bovine PRGS stored under different temperature conditions using a multivariate approach. Concentrations of transforming growth factor beta-1 (TGF-β1), tumor necrosis factor alpha (TNF-α), interleukin-2 (IL-2), and interleukin-6 (IL-6) were evaluated in PRGS samples from six clinically healthy cows stored at −80, −20, 4, 21, and 37 °C for up to 326 h. Data were standardized and explored using hierarchical clustering and heatmaps, and principal component analysis (PCA) based on area under the concentration–time curve (AUC) was used to integrate temporal behavior. Temperature-dependent multivariate signatures were identified, with frozen PRGS clustering separately from samples stored at moderate temperatures. The first two principal components explained 43.0% and 28.9% of the variance and defined an inflammatory–regenerative gradient contrasting TGF-β1/IL-2 versus TNF-α/IL-6 profiles. Linear mixed-effects modeling showed that PC1 was significantly affected by temperature and time (p < 0.001), whereas PC2 was influenced by temperature, time, and their interaction (p ≤ 0.048). Differences among temperatures were minimal at early time points but became more pronounced from 48 to 96 h onward, following a temperature gradient with higher values at moderate temperatures and lower values under frozen conditions. These findings indicate that storage temperature reshapes the integrated biological profile of PRGS, rather than merely preserving mediator composition.