Enhanced combined effect of thymoquinone and transcranial photobiomodulation on cerebral ischemia-induced injuries in animal model.

Various therapeutic approaches to reduce ischemic brain injuries have been somewhat ineffective. Thymoquinone (TQ), a bioactive compound in Nigella sativa, exhibits anti-inflammatory and antioxidant properties. Transcranial photobiomodulation (tPBM), also known as low-level laser therapy (LLLT), has neuroprotective effects by modulating inflammatory and apoptotic pathways. This study investigated whether the administration of TQ as a candidate for combination therapy with tPBM could reduce ischemic brain injuries. Eighty-five Wistar male rats were randomly assigned to five groups: sham, MCAO, TQ, tPBM, and TQ + tPBM. The MCAO group was subjected to middle cerebral artery occlusion (MCAO) surgery. The sham group underwent surgery without filament insertion. The TQ group received 15 mg/kg of intraperitoneal TQ immediately after filament removal. The tPBM group was treated using a Photino brain laser probe (810 nm, 8 mW, and 30.6 J/cm²), which was applied to the cerebral surface of the rats in three sessions, each lasting 2 min. At 24 h After reperfusion, neurological deficit scores (NDS), infarct volume (IV), and brain edema in cortex, piriform cortex-amygdala, as well as the striatum of the rat brain were assessed. Histopathological parameters and brain-derived neurotrophic factor (BDNF) gene expression were also evaluated. The TQ + tPBM group significantly reduced NDS, IV, and brain edema compared to the MCAO group. Increased BDNF gene expression and decreased pyknotic cells were also observed in the TQ + tPBM group. The post-treatment administration of TQ combined with tPBM (in the short term) indicated an enhanced combined effect in reducing ischemic brain damage, potentially through BDNF upregulation.