Administering crocin ameliorates anxiety-like behaviors and reduces the inflammatory response in amyloid-beta induced neurotoxicity in rat.
Clin Exp Pharmacol Physiol. 2021 Mar 8. Epub 2021 Mar 8. PMID: 33686675
Anxiety, hippocampus synaptic plasticity deficit, as well as pro-inflammatory cytokines are involved in Alzheimer's disease (AD). The present study is designed to evaluate the possible therapeutic effect of crocin on anxiety-like behaviors, hippocampal synaptic plasticity and neuronal shape, as well as pro-inflammatory cytokines in the hippocampus using in vivo amyloid-beta (Aβ) models of the AD. The Aβ peptide (1-42) was bilaterally injected into the frontal-cortex. Five hours after the surgery, the rats were given intraperitoneal crocin (30 mg/kg) daily up to 12 days. Elevated plus maze results showed that crocin treatment after bilateral Aβ injection significantlyincreased the percentage of spent time into open arms, frequency of entries and also percentage of entries into open arms as compared with the Aβ group. Also, in the Open Field test the Aβ+crocin group showed higher percentage of spent time in the center and frequency of entries into central zoneas compare with the Aβ treated animals. Furthermore, administering crocin increased the number of soma, dendrites and axonal arbores in the CA1 neurons among the rats with Aβ neurotoxicity. Cresyl violet (CV) staining showed that crocin increased the number of cresyl violet-positive cells in the CA1 region of the hippocampus compared with the Aβ group. Silver-nitrate staining also indicated that crocin reduced neurofibrillary tangle formation induced by Aβ. Crocin treatment attenuated the expression of TNF-α and IL-1β mRNA in the hippocampus compared with the Aβ group. Our results suggested that crocin attenuated Aβ-induced anxiety-like behaviors, neuronal damage and synaptic plasticity loss in hippocampal CA1 neurons may via its anti-inflammatory effects.