The effects of green tea on cognitive impairments in the rat model of Alzheimer’s disease: protection against inflammatory and oxidative damage

ABSTRACT

Introduction

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by a decrement in the number of synapses, an increment in the production of oxygen free radicals and inflammatory cytokines. Green tea (GT) plays a defensive performance in different neurodegenerative conditions, such as cognition deficit. This study investigated the neuroprotective effect of green tea (GT) on cognitive disorder, inflammation, and oxidative stress in the streptozotocin (STZ)- induced AD model.

Materials and Methods

The rats were divided into four groups: (1) Control, (2) GT, (3) Alz, and (4) GT + Alz. AD was induced by the injection of STZ (3 mg/kg, bilaterally, ICV). Morris water maze and passive avoidance tests were done to evaluate the memory and learning of rats. Biochemical parameters were measured with specialized ELISA kits.

Results

Briefly, data analysis revealed that GT administration for 21 days improved memory impairment induced by the injection of STZ. Pretreatment with GT enhanced time spent in the goal quarter and reduced latency time and path length. Furthermore, pretreatment with GT prevented the increment of malondialdehyde (MDA) concentration in STZ-treated rats. As a pro-inflammatory cytokine, tumor necrosis factor- α (TNF-α) concentration was suppressed with the GT pretreatment. Total antioxidant capacity was increased after GT administration in rats treated compared with AD rats.

Conclusions

GT pretreatment attenuated STZ-induced learning and memory impairment through the suppression of TNF-α and MDA concentrations. The beneficial effects of GT on memory could be attributed to its protective effects on oxidative defenses.

KEYWORDS:

• Alzheimer's disease
• green tea
• memory
• inflammation
• learning
• streptozotocin
• malondialdehyde‌
• rat

Acknowledgments

This project was financially supported by research affairs of Zahedan University of Medical Sciences (grant number 9065) and performed in animal care and breeding center, Zahedan University of Medical Sciences (ZAUMS), Zahedan, IRAN.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This project was financially supported by research affairs of Zahedan University of Medical Sciences (grant number 9065) and performed in animal care and breeding center, Zahedan University of Medical Sciences (ZAUMS), Zahedan, IRAN