Palmatine, a natural alkaloid, attenuates memory deficits and neuroinflammation in mice submitted to permanent focal cerebral ischemia

Ischemic stroke is one of the major causes of human morbidity and mortality. The pathophysiology of ischemic stroke involves complex events, including oxidative stress and inflammation, that lead to neuronal loss and cognitive deficits. Palmatine (PAL) is a naturally occurring (Coptidis rhizome) isoquinoline alkaloid that belongs to the class of protoberberines and has a wide spectrum of pharmacological and biological effects. In the present study, we evaluated the impact of Palmatine on neuronal damage, memory deficits, and inflammatory response in mice submitted to permanent focal cerebral ischemia induced by middle cerebral artery (pMCAO) occlusion. The animals were treated with Palmatine (0.2, 2 and 20 mg/kg/day, orally) or vehicle (3% Tween + saline solution) 2 h after pMCAO once daily for 3 days. Cerebral ischemia was confirmed by evaluating the infarct area (TTC staining) and neurological deficit score 24 h after pMCAO. Treatment with palmatine (2 and 20 mg/kg) reduced infarct size and neurological deficits and prevented working and aversive memory deficits in ischemic mice. Palmatine, at a dose of 2 mg/kg, had a similar effect of reducing neuroinflammation 24 h after cerebral ischemia, decreasing TNF-, iNOS, COX-2, and NF- κB immunoreactivities and preventing the activation of microglia and astrocytes. Moreover, palmatine (2 mg/kg) reduced COX-2, iNOS, and IL-1β immunoreactivity 96 h after pMCAO. The neuroprotective properties of palmatine make it an excellent adjuvant treatment for strokes due to its inhibition of neuroinflammation.

Maternal treatment with aripiprazole prevents the development of a valproic acid-induced autism-like phenotype in juvenile male mice

Autism spectrum disorder (ASD) describes a heterogeneous group of neurodevelopmental conditions characterized by deficits in social communication and repetitive behaviors. Aripiprazole (APZ) is an atypical antipsychotic that can safeguard mice against autism-like behavior induced by valproic acid (VPA). In the present study, we examined the effects of maternal treatment with APZ (10 mg/kg) in juvenile mice prenatally exposed to VPA on neurodevelopmental behaviors, social interactions, communication, and working memory, as well as synaptophysin (SYP), synaptosomal-associated protein, 25 kDa (SNAP-25) and microtubule-associated protein 2 (MAP-2) expression in the medial prefrontal cortex (mPFC) and cell viability in the hippocampus. In addition, to evaluate possible APZ interference with the anticonvulsant properties of VPA on pentylenetetrazole (PTZ)-induced seizures were evaluated. Maternal treatment with APZ significantly prevented body weight loss, self-righting, eye-opening, social interactions, social communication, and working memory deficits in mice prenatally exposed to VPA. Additionally, the decrease in the SYP, SNAP-25, and MAP-2 expressions in the mPFC and cell death in the hippocampus was prevented by APZ. Furthermore, APZ (10 mg/kg) did not interfere with the anticonvulsant effect of VPA (15 mg/kg) in animals with PTZ-induced seizures. These findings indicate that maternal treatment with APZ in pregnant mice exposed to VPA protects animals against the ASD-like behavioral phenotype, and this effect may be related, at least in part, to synaptic plasticity and neuronal protection in the PFC and hippocampus. APZ may serve as an effective pharmacological therapeutic target against autistic behaviors in the VPA animal model of ASD, which should be further investigated to verify its clinical relevance.

Vitamin D (VD3) Intensifies the Effects of Exercise and Prevents Alterations of Behavior, Brain Oxidative Stress, and Neuroinflammation, in Hemiparkinsonian Rats

In the present study, we investigated the effects of physical exercise in the presence of Vitamin D3 (VD3), on 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rats. The animals were divided into sham-operated (SO), 6-OHDA-lesioned, and 6-OHDA-lesioned plus VD3 (1 µg/kg, 21 days), in the absence (no exercise, NE) and presence (with exercise, WE) of physical exercise on a treadmill (30 min, speed of 20 cm/s, once a day/21 days). This procedure started, 24 h after the stereotaxic surgery (injections of 6-OHDA into the right striatum). The animals were then subjected to behavioral (rotarod, open field, and apomorphine tests) and their brain areas were dissected for neurochemical, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) determinations, and immunohistochemical studies for tyrosine hydroxylase (TH), dopamine transporter (DAT), and vitamin D receptor (VD3R). The effects on the brain oxidative stress: nitrite/nitrate, glutathione (GSH), and malondialdehyde (MDA) measurements were also evaluated. Behavioral changes of the 6-OHDA lesioned group were improved by exercise plus VD3. Similar results were observed in dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations increased by exercise and VD3, compared with SO groups. Additionally, tyrosine hydroxylase (TH) and dopamine transporter (DAT) immunoexpressions were decreased in the 6-OHDA-lesioned groups, with values normalized after exercise and VD3. The VD3 receptor immunoexpression decreased in the 6-OHDA (NE) group, and this was attenuated by exercise, especially after VD3. While 6-OHDA lesions increased, VD3 supplementation decreased the oxidative stress, which was intensified by exercise. VD3 showed neuroprotective properties that were intensified by physical exercise. These VD3 actions on hemiparkinsonian rats are possibly related to its antioxidant and anti-inflammatory effects.

Neuroprotective Activities of Spirulina platensis in the 6-OHDA Model of Parkinson's Disease Are Related to Its Anti-Inflammatory Effects

Spirulina platensis (SPI) is a cyanobacterium, presenting anti-inflammatory and antioxidant actions. Considering the importance of inflammation and oxidative stress in Parkinson's disease (PD), SPI neuroprotective effects were evaluated in a model of PD. Male Wistar rats were divided into: sham-operated (SO), untreated 6-OHDA and 6-OHDA treated with SPI (25 and 50 mg/kg, p.o.). The 6-OHDA was injected into the right striata and SPI treatments started 24 h later for 2 weeks. The SO and untreated 6-OHDA-lesioned groups were administered with distilled water, for the same period. Afterwards, the animals were subjected to the apomorphine-induced rotational test and euthanized for striatal measurements of DA and DOPAC, nitrite and TBARS and immunohistochemistry assays for TH, DAT, iNOS and COX-2. SPI reduced the apomorphine-induced rotational behavior, DA and DOPAC depletions and nitrite and TBARS increases, at its high dose. Furthermore, TH and DAT immunoreactivities in the lesioned striatum of the untreated 6-OHDA-lesioned group were attenuated by SPI. Similarly, immunoreactivities for iNOS and COX-2 were also decreased after SPI treatments. In conclusion, we showed that behavioral and neurochemical alterations in hemiparkinsonian rats were partly reversed by SPI, characterizing the neuroprotective potential of Spirulina and stimulating translational studies focusing on its use as an alternative treatment for PD.

Neuroinflammatory response to experimental stroke is inhibited by eriodictyol

BACKGROUND

Cerebral ischemia is a common disease and one of the most common causes of death and disability worldwide. The lack of glucose and oxygen in neuronal tissue leads to a series of inflammatory events, culminating in neuronal death. Eriodictyol is a flavonoid isolated from the Chinese herb Dracocephalum rupestre that has been proven to have anti-inflammatory properties.

HYPOTHESIS/PURPOSE

Thus, the present study was designed to explore whether eriodictyol has neuroprotective effects against the neuronal damage, motor and memory deficits induced by permanent middle cerebral artery occlusion (pMCAO) in mice.

STUDY DESIGN

Animals were orally treated with eriodictyol (1, 2 and 4mg/kg) or vehicle (saline) 30min before pMCAO, 2h after, and then once daily for the following five days.

METHODS

The parameters studied were neuronal viability, brain infarcted area; sensorimotor deficits; exploratory activity; working and aversive memory; myeloperoxidase (MPO) activity; TNFα, iNOS and GFAP immunoreactivity.

RESULTS

The treatment with eriodictyol prevented neuronal death, reduced infarct area and improved neurological and memory deficits induced by brain ischemia. The increase of MPO activity and TNF-α, iNOS and GFAP expression were also reduced by eriodictyol treatment.

CONCLUSION

These findings demonstrate that eriodictyol exhibit promising neuroprotection effects against the permanent focal ischemia cerebral injury in the mice experimental model and the underlying mechanisms might be mediated through inhibition of neuroinflammation.

Catechin attenuates behavioral neurotoxicity induced by 6-OHDA in rats

This study was designed to investigate the beneficial effect of catechin in a model of Parkinson's disease. Unilateral, intrastriatal 6-hydroxydopamine (6-OHDA)-lesioned rats were pretreated with catechin (10 and 30 mg/kg) by intraperitoneal (i.p.) injection 2h before surgery and for 14 days afterwards. After treatments, apomorphine-induced rotations, locomotor activity, working memory and early and late aversive memories were evaluated. The mesencephalon was used to determine the levels of monoamines and measurement of glutathione (GSH). Immunohistochemical staining was also used to evaluate the expression of tyrosine hydroxylase (TH) in mesencephalic and striatal tissues. Catechin administration attenuated the increase in rotational behavior and the decrease in locomotor activity observed in lesioned rats. Although catechin did not rescue the impairment of late aversive memory, it protected the animals against 6-OHDA-induced working memory deficits. Furthermore, catechin treatment restored GSH levels, and significantly increased dopamine and DOPAC content, and TH-immunoreactivity in 6-OHDA-lesioned rats. Catechin protected 6-OHDA-lesioned rats due to its antioxidant action, indicating that it could be useful as an adjunctive therapy for the treatment of Parkinson's disease.

Safety evaluation of Elixir paregorico® in healthy volunteers: a phase I study

A liquid alcoholic extract of Papaver somniferum named Elixir Paregorico® is extensively used for diarrheal diseases in Brazil. Its increased popularity has brought concerns and fears over the safety of this herbal product. Given the lack of investigative clinical studies, in this regard, this study investigated whether Elixir Paregorico® administration causes any noticeable toxic effects in healthy volunteers. In all, 28 middle-aged healthy male ( n = 14) and female ( n = 14) were enrolled. After screening and a washout period, eligible subjects received four oral doses per day of Elixir Paregorico® (3 mL diluted in 30 mL of water) over a 10-day period. Altogether, all 28 participants completed the study. The results of hematological and biochemical tests performed pre and post-treatment were within the normal range. In both male and female volunteers, there were no statistical differences ( P > 0.05) in the results of clinical and laboratory tests performed at screening, on 5th and 10th day visits, and at final assessment. Although mild adverse events were related, which subsided spontaneously, no serious untoward reactions were reported following Elixir Paregorico® administration. To our knowledge, this is the first demonstration that Elixir Paregorico® administered four times a day for 10 days is safe and does not cause any noticeable toxic effect in healthy volunteers.