Protective role of Eugenol against the destructive effects of lead on conditioned fear memory in male rats with post-traumatic stress disorder-related behavioral traits.

Introduction: Post-traumatic stress disorder (PTSD) is a consequence of living in today's stressful society. Patients have difficulty forgetting traumatic events. lead pollution has many effects on the nervous system, one of which is memory and learning disorders. The herbal medicine Eugenol has a beneficial effect on memory. Aim: This study aims to investigate the protective effect of Eugenol on lead-induced memory impairments in stressed rats. Methods: In the first experiment, the animals were divided into three groups: SPS+Saline, SPS+Pb, and naïve. The SPS+Saline, SPS+Pb groups received normal saline and lead through gavage for 21 days, while the sham group remained untreated. Rats were subjected to the modified single prolonged stress model. Memory tests were conducted one week later, evaluating freezing levels in three consecutive tests over three days. In the second experiment, rats were divided into a SPS+Pb+Saline and three treatment groups. The SPS+Pb+Saline group received daily saline injections, while the other groups received different doses of Eugenol (25, 50, and 100 mg/kg). Memory tests similar to the first experiment were conducted. Results: The results showed significantly higher immobility levels in the SPS+Saline and SPS+Pb groups compared to the sham. Additionally, the SPS+Pb group had a significant higher immobility compared to the SPS+Saline group. In the second experiment, the SPS+Pb+EU 25 group showed a significant lower freezing compared to the SPS+Pb+Saline group. Additionally, freezing in the SPS+Pb+EU 50 and SPS+Pb+EU 100 groups was significantly higher than in the SPS+Pb+EU 25 group. The SPS+Pb+EU 50 group showed a significant higher freezing compared to the SPS+Pb+Saline group. Conclusion: lead acetate exacerbated memory impairments in stressed rats and Eugenol, particularly at a dose of 25 mg/kg, improved these impairments. Therefore, Eugenol has the potential to partially reduce the negative effects of lead on memory in individuals with PTSD.

Pre-treatment by Rosemary Extract or Cell Transplantation Improves Memory Deficits of Parkinson's Disease: When Tradition Meets the Future

ABSTRACT The therapeutic effect of adipose tissue-derived stem cells (ADSCs) or RE on hippocampal neurogenesis and memory in Parkinsonian rats were investigated. Male rats were lesioned by bilateral intra-nigral injections of 6-OHDA and divided into six groups: 1. Lesion 2 and 3: RE and water groups were lesioned rats pretreated with RE or water, from 2weeks before neurotoxin injection and treated once a day for 8weeks post lesion. 4&5: Cell and α-MEM (α-minimal essential médium) received intravenous injection of BrdU-labeled ADSCs or medium, respectively from 10days post lesion until 8weeks later. 6: Sham was injected by saline instead of neurotoxin. Memory was assessed using Morris water Maze (MWM), one week before and at 1, 4 and 8weeks post 6-OHDA lesion. After the last probe, the animals were sacrificed and brain tissue obtained. Paraffin sections were stained using cresyl violet, anti-BrdU (Bromodeoxyuridine / 5-bromo-2'-deoxyuridine), anti-GFAP (Glial fibrillary acidic protein) and anti-TH antibodies. There was a significant difference of time spent in the target quadrant between groups during probe trial at 4 and 8 weeks' post- lesion. Cell and RE groups spent a significantly longer period in the target quadrant and had lower latency as compared with lesion. Treated groups have a significantly higher neuronal density in hippocampus compared to water, α-MEM and lesion groups. BrdU positive cells were presented in lesioned sites. The GFAP (Glial fibrillary acidic protein) positive cells were reduced in treated and sham groups compared to the water, α-MEM and lesion groups. Oral administration of RE (Rosemary extract) or ADSCs injection could improve memory deficit in the Parkinsonian rat by neuroprotection.

Investigating the role of the amygdala orexin receptor 1 in memory acquisition and extinction in a rat model of PTSD.

Understanding the mechanisms underlying memory is essential for the treatment of post-traumatic stress disorder (PTSD). Orexin, as a lateral hypothalamic (LH) neuropeptide, interferes with the stages of memory, primarily through the orexin receptor1 (Orx1R). The aim of this study was to evaluate the effects of amygdala Orx1R in the acquisition and extinction processes of PTSD modeled in animals. In three experiments, rats were divided into three groups: control (Naïve), shock (receiving a foot shock), and PTSD (experiencing Single prolonged stress (SPS) method). The first experiment aimed to evaluate LH activity in PTSD modeled rats. The second and third experiments aimed to evaluate the effects of Orx1R in the acquisition and extinction of fear memory in PTSD modeled animals. SB334867 (SB) or its solvent was microinjected into the amygdala and the rats were subjected to conditioning thereafter. In the second group, we used a single injection after conditioning. In the third group, we used three consecutive injections (one after each memory test). Some behaviors and Orx1R expression were evaluated. The freezing response was significantly longer in the PTSD group than on the control. Similarly, anxiety and sensitized fear were also intensified. CFos expression levels in LH was higher in the PTSD group. Inhibition of Orx1R in the amygdala significantly decreased memory acquisition, diminished anxiety, and decreased the sensitized fear in the SB group. Applying SB to the amygdala after each fear memory test significantly decreased freezing. Expression of Orx1R was significantly higher following fear conditioning. These results indicate a likely involvement of the orexin and amygdalar Orx1R in memory acquisition and in extinction of PTSD.