Royal jelly improves learning and memory deficits in an amyloid ß-induced model of Alzheimer's disease in male rats: Involvement of oxidative stress.

Alzheimer's disease (AD) as the commonest type of dementia is associated with the cognitive function failure. Oxidative stress performs an essential role in the progression of AD. Royal jelly (RJ) is a natural product of bees with antioxidant and anti-inflammatory properties. The present research aimed to investigate the possible protective effect of RJ on learning and memory in a rat model of Aß-induced AD. Forty male adult Wistar rats were equally distributed into five groups: control, sham-operated, Aß (receiving intracerebroventricular (ICV) injection of amyloid beta (Aß1-40)), Aß + RJ 50 mg/kg, and Aß + RJ 100 mg/kg. RJ was administered daily post-surgery by oral gavage for four weeks. Behavioral learning and memory were examined using the novel object recognition (NOR) and passive avoidance learning (PAL) tests. Also, oxidative stress markers, such as malondialdehyde (MDA), total oxidant status (TOS) and total antioxidant capacity (TAC), were assessed in the hippocampus. Aß reduced step-through latency (STLr) and increased time spent in the dark compartment (TDC) in the PAL task and also decreased discrimination index in the NOR test. Administration of RJ ameliorated the Aß-related memory impairment in both NOR and PAL tasks. Aß decreased TAC and increased MDA and TOS levels in the hippocampus, whereas RJ administration reversed these Aß-induced alterations. Our results indicated that RJ has the potential to ameliorate learning and memory impairment in the Aß model of AD via attenuating oxidative stress.

Knowledge, attitudes, risk perceptions, and practices of adults toward COVID-19: a population and field-based study from Iran.

OBJECTIVES: To determine peoples' knowledge, attitudes, risk perceptions, and practices to provide policymakers pieces of field-based evidence and help them in the management of the COVID-19 epidemic. METHODS: This population-based survey was conducted using multi-stage stratified and cluster sampling in Shiraz, Iran. A total of 1331 persons were interviewed. The questionnaires were completed by face-to-face interviews. Univariable and multivariable (linear regression) data analyses were done using SPSS. RESULTS: The participants answered 63% of questions regarding knowledge, and 78% of questions regarding practice correctly. Only, 4.8% knew about common symptoms of COVID-19 and 7.3% about warning signs that require referral to hospitals. Males, lower educated people, and elders had a lower level of knowledge and poorer practices. Knowledge was also lower in the marginalized (socially deprived) people. Knowledge and practices' correlation was 37%. Overall, 43.6% considered themselves at high risk of COVID-19, and 50% considered it as a severe disease. This disease had negative effects on most participants' routine activities (69.1%). The participants preferred to follow the news from the national TV/Radio, social networks, and foreign satellite channels, respectively. CONCLUSIONS: Encouragement of people to observe preventive measures and decreasing social stress, especially among males, lower educated people, elders, and marginalized groups, are highly recommended.