Comparison of nerve fibers in the deciduous first and second molar teeth: an in vitro study

Introduction: Sensory nerves of the tooth pulp have been evolved in both deciduous and permanent teeth for conducting possible damages to the teeth. Although it has been reported that the deciduous tooth�s pulp is histologically similar to permanent teeth, the difference in the density of nerves between the first and second deciduous molars has been reported in no studies. Aim: The aim of the study was to investigate the histological assay of pulpal nerves and assess the relationship between diameter and density of nerve fibres in the first and second deciduous molar teeth. Materials and methods: In this in vitro study, 15 deciduous first and 16 deciduous second extracted from molar teeth belonging to children aged from 5 to 8 years were studied. After fixation, the decalcified teeth were sectioned and then stained with silver solution and calcitonin gene-related peptide (CGRP) antibody. The mean diameter of myelinated fibres, un-myelinated fibres, and density of peripheral network fibres of dental pulp were examined. Results: The results showed that the mean diameter of myelinated and non-myelinated fibres and density of nerve fibres were significantly more in the second molars (4.269, 2.328 µm, 2.6 fibres per unit area) compared to the first molar teeth (3.793, 2.093 µm, 1.8 fibres per unit area) (P < 0.032, 0.019, 0.003, respectively). An important finding in this study, which is reported for the first time, is the presence of fatty cells (adipocytes) in pulp tissue of some of the first deciduous molars as well as the second molars. Conclusions: Based on the results of the current study, differences between nerve fibres of first and second molar teeth are significant. It could be concluded that the less sensitivity to pain of the first deciduous molars compared with the second deciduous molars, is due to the lower nerve density of this tooth. © 2020, European Academy of Paediatric Dentistry

Date seed extract ameliorates β-amyloid-induced impairments in hippocampus of male rats

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder among the elderly. Because the existing treatments for Alzheimer's disease only offer limited symptomatic alleviation, more efficient therapeutic agents are urgently needed. Date seed is a hepatoprotective and neuroprotective agent. Date seed extract (DSE) has bioactive components like phenolics, flavonoids, and vitamins. In view of the ameliorative effects of DSE against an oxidative injury, the current study was designed to reveal whether DSE has a neuroprotective resource in the rat model of Alzheimer's disease. In the current study, 24 adult male Sprague-Dawely rats were divided into three groups (n = 8) of: Sham (Distilled Water, 3 μl intracerebroventricular (ICV) injection), β-Amyloid (β-amyloid, 3 μl ICV injection), and DSE-treated groups (80 mg/kg, Intraperitoneal (IP) injection), for 12 days. Twelve days after Alzheimer induction, behavioral analysis, the Morris Water Maze (MWM), as well as western blot and histological studies were performed to reveal the neuroprotective potential of DSE in rats. Administration of DSE significantly restored memory and learning impairments induced by Aβ in the MWM test. DSE significantly decreased the caspase-3 expression level in the treated group. In addition, DSE reduced the number of degenerated neurons in the hippocampal CA1 subfield of the DSE treated rats. These results demonstrate that DSE may have beneficial effects in the prevention of Aβ-induced Alzheimer in a rat model. Date seed extract may have advantageous effects in preventing Alzheimer's disease in male rats. © 2017 Elsevier Masson SA

Biogenic selenium nanoparticles target chronic toxoplasmosis with minimal cytotoxicity in a mouse model

Introduction. Nanoparticles (NPs) have numerous biological benefits due to their large surface-volume ratio and convenient entry into cells compared to other particles. Previous research has shown the antimicrobial properties of biogenic selenium NPs (SeNps) and their effects on cellular immunomodulatory cytokines that play a key role in controlling infections. Aim. This study aimed to evaluate the therapeutic effects of SeNPs against chronic toxoplasmosis in mice. Methodology. Infected mice with Toxoplasma gondii (Tehran strain) were orally treated with SeNPs at doses of 2.5, 5 and 10 mg kg�1 once a day for 14 days. On the fifthteenth day, the mean number of brain-tissue cysts and the mRNA levels of TNF-α, IL-12, IL-10, IFN-γ and inducible nitric oxide synthase (iNOS) in the mice of each group were recorded. Moreover, serum clinical chemistry factors in the treated mice were examined to determine the safety of SeNPs. Results. The mean number of tissue cysts was significantly (P&lt;0.001) decreased in mice treated with SeNPs in a dose-dependent manner compared with the control group. The mRNA levels of inflammatory cytokines were significantly increased in mice treated with SeNPs at a dose of 10 mg kg�1 compared with the control subgroup (P&lt;0.05). No significant variation (P&gt;0.05) observed in clinical chemistry parameters among the mice in the control subgroup compared with those treated with SeNPs. Conclusion. The findings demonstrated the therapeutic effects of SeNPs with no considerable toxicity against latent toxoplasmosis in the mouse model. Nevertheless, further studies are obligatory to reveal the exact anti-Toxoplasma mechanisms of SeNPs. © 2020 The Author

Investigating the neuroprotective effects of resveratrol on encephalopathy induced by bile duct ligation in male rats

Hepatic encephalopathy (HE) is a complex neuropsychiatric disorder without definitive treatment. The precise mechanism that leads to HE is not fully understood. Resveratrol (RES) is a polyphenol compound with antioxidant and anti-inflammatory properties that mitigates the progression of different illnesses such as inflammatory and ischemic diseases. This study reports the effects of RES on neuronal injures in bile duct-ligated rats. The rats were randomly distributed into three groups including sham, bile duct ligation (BDL), and BDL + RES. Behavioral and biochemical studies were performed to evaluate neuronal injuries. The obtained data indicate that BDL experienced a balanced impairment and an increase in the hepatic enzymes. RES had a preserving role in the treated animals. Moreover, RES treatment declined neuronal injuries induced by BDL. For the first time, the results of this study showed that RES has beneficial effects in the rat model of HE probably because of its antioxidant and anti-inflammatory properties. © 2020 by the authors. T

Inhibition of protease-activated receptor 1 (PAR1) ameliorates cognitive performance and synaptic plasticity impairments in animal model of Alzheimer�s diseases

Introduction: Alzheimer�s disease (AD) is a progressive brain disorder accompanied with synaptic failures and decline in cognitive and learning processes. Protease-activated receptor 1 (PAR1) is the major thrombin receptor in the brain that is implicated in synaptic plasticity and memory formation. In the current study, we hypothesized that inhibition of PAR1 would theoretically prevent amyloid beta (Aβ) accumulation in the brain and then contribute to reduce risk of AD. The aim of the present study was to evaluate the effect of PAR1 inhibition by using SCH (as an inhibitor of PAR1) on spatial learning, memory, and synaptic plasticity in the CA1 region of the hippocampus in rat model of Alzheimer�s disease. Methods: For the induction of Alzheimer�s disease, amyloid beta (Aβ) 1�42 was injected in the CA1 region of the hippocampus. The rats were divided into four groups: group I (surgical sham); group II rat mode of Alzheimer�s disease (AD); group III (SCH) (25 μg/kg) intraperitoneally (i.p.), and group IV (AD + SCH). After 14 days of protocol, the rats in group III received SCH and 30 min after injection behavioral and electrophysiological tests were performed. Learning and memory ability was assessed by Morris water maze and novel object recognition tests. Extracellular evoked field excitatory postsynaptic potentials (fEPSP) were recorded in the stratum radiatum of the CA1 area. Results: Our results showed that AD rats showed impairments in learning and memory, and long-term potentiation (LTP) was not induced in these rats. However, injection of SCH overcame the AD-induced impairment in LTP generation in the CA1 area of the hippocampus and improved learning and memory impairment. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature

Ovarian hormones prevent methamphetamine-induced anxiety-related behaviors and neuronal damage in ovariectomized rats

Methamphetamine (METH) may cause long�lasting neurotoxic effects and cognitive impairment. On the other hand, the ovarian hormones estrogen and progesterone have neuroprotective effects. In the current study, we aimed to examine the effects of estrogen and progesterone on anxiety�like behavior and neuronal damage in METH�exposed ovariectomized (OVX) rats. Three weeks after ovariectomy, the animals received estrogen (1 mg/kg, i.p.), or progesterone (8 mg/kg, i.p.), or estrogen plus progesterone (with the same doses), or vehicle during 7 consecutive days (days 22�28). On day 28, OVX rats were exposed to a single�day METH regimen (6 mg/kg, four s.c. Injections, with 2 h interval) 30 min after the hormone treatment. The next day (on day 29), the animals were assessed for anxiety�related behaviors using the open field and elevated plus�maze tasks. The animals were then sacrificed and brain water content, cell apoptosis and expression of IL-1β were evaluated. The findings showed that treatment with estrogen or progesterone alone in METH�exposed rats significantly improved hyperthermia, anxiety�like behavior, neuronal damage, and inflammation in the CA1 area. Also, treatment with estrogen plus progesterone improved hyperthermia and brain edema. Taken together, the findings suggest that treatment with ovarian hormones can partially prevent hyperthermia and anxiety�related behaviors induced by METH in OVX rats, which could be accompanied by their neuroprotective effects in the hippocampus. © 202