Abstract
Introduction: The brain-derived neurotrophic factor (BDNF) and transcription nuclear factor erythroid 2-related factor-2 (NRF-2) play an important role in Alzheimer’s disease (AD). However, the interactive involvement of BDNF and NRF-2 in respect to antioxidant mechanisms in different parts of the AD brain is still unclear. Considering the above condition, used S-nitrosoglutathione (GSNO) to examine whether it modulates the BDNF and NRF-2 levels to activate signaling pathway to promote antioxidant levels in AD brains. Method: AD was induced by intracerebroventricular infusion of streptozotocin (ICV-STZ, 3 mg/kg) in Wistar rats. The effect of GSNO was analyzed by evaluating the retention of memory in months 1, 2, and 3. After the behavior study, rats were sacrificed and accessed the amyloid beta (Aβ)-40, Aβ42, glutathione (GSH), BDNF, and NRF-2 levels in the hippocampus, cortex, and amygdala tissue. Results: Pretreatment with GSNO (50 µg/kg/intraperitoneal/day) restored the BDNF, and NRF-2 levels toward normalcy as compared with ICV-STZ + saline-treated animals. Also, GSNO treatment reversed the oxidative stress and increased the GSH levels toward normal levels. Further, reduced Aβ levels and neuronal loss in different brain regions. As a result, GSNO treatment improved the cognitive deficits in ICV-STZ-treated rats. Conclusion: The results showed that endogenous nitric oxide donor GSNO improved the cognitive deficits and ICV-STZ-induced AD pathological conditions, possibly via attenuating the oxidative stress. Hence, the above finding supported that GSNO treatment may activate BDNF and NRF-2 antioxidant signaling pathways in the AD brain to normalize oxidative stress, which is the main causative factor for ICV-STZ-induced AD pathogenesis.
Plain Language Summary
This work is mainly focused on the investigation of the antioxidant activity of S-nitrosoglutathione (GSNO) in intracerebroventricular infusion of streptozotocin (ICV-STZ)-induced Alzheimer’s disease (AD) in rats. GSNO is an endogenous nitric oxide donor and has potent antioxidant activities. Our study revealed for the first time that GSNO may have antioxidant activities in AD by improving the endogenous antioxidant defense system. Further, GSNO treatment improved spatial retention and contextual fear memory in rats. Also, GSNO treatment decreased the AD neuropathological parameters (neuronal damage, amyloid beta-Aβ40, Aβ42) and improved the neuroprotective parameters (GSH, brain-derived neurotrophic factor, and nuclear factor erythroid 2-related factor-2) levels in AD brain tissues. These findings indicate that GSNO activates the neuronal antioxidant defense system and normalizes oxidative stress in the AD brain.