Injection of Collagen Binding Domain-Brain Derived Neurotrophic Factor Promotes SIRT1 Expression: Improving Neuroinflammation in Experimental Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a severe cerebrovascular disease, often leading to neuroinflammation and neuronal damage. Activation of the Nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome is closely associated with post-SAH neuroinflammation, while activation of Nicotinamide Adenine Dinucleotide (NAD)-dependent deacetylase sirtuin-1 (SIRT1) has neuroprotective effects. This study aimed to investigate the impact of injectable Collagen Binding Domain-Brain Derived Neurotrophic Factor (CBD-BDNF) on neuroinflammation and neuronal damage following SAH. After establishing the SAH model, experimental animals were divided into three groups: sham surgery group (Sham), SAH group, and SAH+neuroregenerative scaffold (CBD-BDNF treatment) group. Behavioral performance was evaluated using neurofunctional deficit, beam balance, and Y-maze tests. Expression of inflammatory factors and essential proteins was quantitatively analyzed using Enzyme-Linked Immunosorbent Assay (ELISA) kits and immunoblotting. Terminal deoxynucleotidyl transferase dUTP Nick End Labeling (TUNEL) staining was used to assess cell apoptosis. To further investigate the mechanism of action of CBD-BDNF on SIRT1, the model animals were treated with EX527 (SIRT1 inhibitor) for comparative studies. Neurological deficit tests, CBD-BDNF improves functional outcomes after SAH. Compared to the SAH group, the SAH+neuroregenerative scaffold group showed significantly increased expression of SIRT1 protein and significantly decreased expression of NLRP3, Apoptosis-associated speck-like protein containing a CARD (ASC), and c-caspase-1. The inflammatory cytokines Interleukin-1 beta (IL-1β), IL-6, and IL-18 levels also significantly decreased in the SAH+neuroregenerative scaffold group. Additionally, animals in the SAH+neuroregenerative scaffold group showed better neurofunctional recovery in neurofunctional deficit and beam balance tests. The number of apoptotic cells significantly decreased in the SAH+neuroregenerative scaffold group compared to the SAH group. However, when SIRT1 was inhibited with EX527, the aforementioned neuroprotective effects were reversed, indicating the involvement of CBD-BDNF through SIRT1 activation. This study demonstrates that injectable CBD-BDNF can significantly alleviate neuroinflammation and neuronal damage resulting from SAH by blocking NLRP3 inflammasome activation and promoting SIRT1 expression. These findings provide a new therapeutic