Salvianolic acid B exerts cerebroprotective effects after traumatic brain injury via Nrf2-dependent antioxidant and anti-inflammatory cascades

Background

Oxidative stress and inflammatory responses play crucial roles in the development of secondary brain injury following traumatic brain injury (TBI). Thus, this study aimed to investigate the potential cerebroprotective effects of salvianolic acid B (SalB) in mitigating oxidative stress and inflammatory responses post-TBI through the activation of Nrf2.

Purpose

This study aims to investigate the potential cerebroprotective effects of SalB in ameliorating oxidative stress and inflammatory responses following TBI by activating Nrf2, thereby laying a foundation for TBI treatment.

Study design

Controlled cortical impact and hydrogen peroxide were employed to replicate TBI in animal and cellular models, respectively.Behavioral studies predict neural function, Western Blot (WB) predicts oxidative stress, immunofluorescence and ELISA predict inflammatory response.The Nrf2 inhibitor ML385 was employed to investigate the involvement of the Nrf2 pathway in mediating the protective effects of SalB.

Methods

SalB was delivered via intraperitoneal injection 1 h after TBI induction, with its neuroprotective efficacy evaluated across a range of concentrations. In the cellular assay, SalB was used to incubate cells simultaneously with H₂O₂. WB analysis was employed to quantify protein levels, while malondialdehyde, glutathione, superoxide intensity, and reactive oxygen radical probes were utilized to evaluate oxidative stress. Immunofluorescence and ELISA techniques were used to characterize microglia phenotype and inflammatory response. Behavioral assays were also conducted to evaluate neurological function. The Nrf2 inhibitor ML385 was employed to investigate the involvement of the Nrf2 pathway in mediating the protective effects of SalB.

Results

Animal and cellular experiments indicate that SalB can mitigate oxidative stress through the Nrf2/Peroxiredoxin 2 pathway, and reduce inflammatory response via the Nrf2/Toll-like receptor 4/Myeloid differentiation primary response protein 88 pathway in a dose-dependent manner. Consequently, SalB demonstrates efficacy in enhancing neurological function following TBI. Conversely, the inhibitory effects of ML385 counteract the antioxidant and anti-inflammatory properties of SalB.

Conclusions

SalB exerts its beneficial effects post-TBI through Nrf2-dependent antioxidants and as anti-inflammatory responses.