Effects of abscisic acid on Streptozotocin-induced changes in hippocampal expression of cyclooxygenase-۲ (COX-۲) and phosphorylated ERK signaling (p-ERK) in male rats

Abstract Introduction: Central administration of STZ (Streptozotocin) induces oxidative damage, neuroinflammation, cholinergic deficits, β-amyloid and tau protein accumulation in the brain. Abscisic acid (ABA) as a phytohormone is produced in a variety of animal tissues, including brain. Recently data show it has been involved in a wide spectrum of activities in CNS including, learning and memory and pain regulation. Here, the alternative effects of abscisic acid and the possibility of involving PKA and PPARβ/δ receptors, on Streptozotocin-induced changes in hippocampal expression of cyclooxygenase-۲ (COX-۲) and ERK signaling (p-ERK) in male Wister rats was investigated. Methods: STZ was injected intracerebroventricularly (i.c.v.) (۳ mg/kg), ABA was administrated alone (۱۰ μg/rat, i.c.v.) or accompanied with PPARβ/δ receptor antagonist (GSK۰۶۶۰, ۸۰ nM/rat) or selective inhibitor of PKA (H۸۹, ۸۰nM/rat) for ۱۴ days. Western blot analysis was used to indicate changes in hippocampal COX-۲ and p-ERK expression. Results: The results showed that STZ produced a significant increase in hippocampal expression of COX-۲ and a decrease in expression of p-ERK. ABA significantly prevented the effects of STZ. However, ABA effects were blocked by PPARβ/δ receptor antagonist (GSK۰۶۶۰) and selective inhibitor of PKA (H۸۹). Conclusions: It seems that the ABA moderates STZ-induced neuronal inflammation and ERK signaling deficiency by PPARβ/δ receptor and PKA signaling. Keywords: Abscisic acid; Streptozotocin; COX-۲; p-ERK; Rats

Keywords:

Abscisic acid , Streptozotocin , COX-۲ , p-ERK , Rats