Lappaconitine protects SH-SY5Y cells from TNF-α-induced mitochondrial apoptosis by blocking the Bax-dependent Caspase-3 signaling pathway

Lappaconitine (LA) is a diterpene alkaloid isolated from Aconitum species and has been used in traditional Chinese medicine as an analgesic. Previous studies have also suggested that LA exerts anti-inflammatory and immunomodulatory effects. Neuroinflammation and oxidative stress, both of which are associated with mitochondrial dysfunction and apoptosis, contribute to the development and maintenance of neuropathic pain. We hypothesized that LA may protect SH-SY5Y cells against inflammation- and apoptosis-associated injury. To investigate whether LA attenuates TNF-α-induced inflammatory injury and apoptosis in SH-SY5Y cells and to explore the potential mechanisms involved. SH-SY5Y cells were pretreated with LA (0.1 or 1 μM) for 24 h and subsequently exposed to TNF-α (10 ng/mL) for 12 h. Apoptosis, mitochondrial function, inflammatory cytokine production, and the expression of mitophagy-related proteins were assessed in LA-pretreated and non-pretreated cells. LA pretreatment (0.1 or 1 μM) reduced apoptosis in TNF-α-exposed SH-SY5Y cells, increased Bcl-2 expression, and decreased the expression of Bax, Caspase-3, and Caspase-9. LA pretreatment also suppressed NF-κB activation and reduced IL-1β and IL-6 production. In addition, LA preserved mitochondrial integrity, as indicated by maintenance of mitochondrial membrane potential, reduced cytochrome c release, and decreased ROS accumulation. The expression of the mitophagy-related proteins PINK1 and Parkin was also increased following LA pretreatment. LA attenuated TNF-α-induced inflammatory injury and apoptosis in SH-SY5Y cells. These protective effects were associated with modulation of apoptosis-related signaling, suppression of inflammatory responses, preservation of mitochondrial function, and increased expression of PINK1/Parkin-related proteins. These findings suggest that LA may exert neuroprotective effects under inflammatory conditions.