Effect of Green Tea Hydro Alcoholic Extract on Aquaporin4 Expression in Cerebral Cortex, as a Potential TherapeuticWay to Alleviate Edema Symptoms

Aquaporin4 (AQP4) is the main water channel in the brain that has important role in water transport across blood- brain- barrier. It has been proved that intracranial pressure and also expression of AQP4 increase in some disorders such as Hydrocephalus, Hyponatremia, cytotoxic oedema and brain tumours and drugs that can decrease the expression of this AQP can offer some treatment for these disorders. The aim of this study was to determine whether green tea extract (GTE) can down regulate the Aquaporin4 protein level in brain cortex. This research is a laboratory experimental study. 40 Wister rats (4-6 weeks) were randomly divided into 4 groups as follows: untreated control group, sham group treated intra peritoneally (IP) with 200 μl saline (solvent GTE), experimental1&2treated IP with 100& 200 mg/kg GTE dissolved in 200 μl saline. After 6 hours, expression of AQP4 in control, sham, and experimental groups were tested by immunohistochemistry and western blotting. Results from immunohistochemistry and western blotting showed that GTE can down regulate the AQP4 expression level on dose-dependent manner in brain cortex. It is suggested that GTE has potential to reduce the level of AQP4 protein in brain cortex and it can be useful as a herbal medicine to reduce intracranial pressure in diseases such as hyponatremia, cytotoxic oedema, brain tumours and etc.