TGF-β2 exerts neuroprotective effects via inhibition of astrocyte-mediated inflammatory responses.

Traumatic brain injury (TBI) is a severe neurological condition associated with complex pathological cascades. Transforming growth factor-β2 (TGF-β2) is a pleiotropic cytokine that participates in multiple cellular events in the central nervous system; however, its potential protective role and molecular mechanisms in the context of TBI-induced neuronal injury have not been fully elucidated. In this study, we observed that TGF-β2 expression was markedly increased following TBI, with peak expression at day 7 post-injury. Using an in vitro LPS-induced inflammatory model, we found that exogenous TGF-β2 treatment significantly reduced the expression of pro-inflammatory factors TNF-α, IL-1β, and IL-6, as assessed by qRT-PCR, Western blot, and ELISA. Co-culture of neurons with conditioned medium from LPS-stimulated astrocytes revealed that TGF-β2 overexpression indirectly attenuated neuronal apoptosis and enhanced neuronal viability, as demonstrated by CCK-8, TUNEL staining, and molecular analyses. Mechanistic investigations suggested that the anti-inflammatory and anti-apoptotic effects of TGF-β2 may be mediated through activation of the Smad3 signaling pathway. Consistently, in vivo experiments indicated that TGF-β2 overexpression alleviated motor dysfunction and reduced neuronal apoptosis in a TBI mouse model. Collectively, these findings provide evidence for a protective role of TGF-β2 in inflammatory neuronal injury and offer insights into potential molecular targets for TBI therapeutic development.