Cognitive impairment and hippocampal neuronal damage in β-thalassaemia mice

β-Thalassaemia is one of the most common genetic diseases worldwide. During the past few decades, life expectancy of patients has increased significantly owing to advance in medical treatments. Cognitive impairment, once has been neglected, has gradually become more documented. Cognitive impairment in β-thalassaemia patients is associated with natural history of the disease and socioeconomic factors. Herein, to determined effect of β-thalassaemia intrinsic factors, 22-month-old β-thalassaemia mouse was used as a model to assess cognitive impairment and to investigate any aberrant brain pathology in β-thalassaemia. Open field test showed that β-thalassaemia mice had decreased motor function. However, no difference of neuronal degeneration in primary motor cortex, layer 2/3 area was found. Interestingly, impaired learning and memory function accessed by a Morris water maze test was observed and correlated with a reduced number of living pyramidal neurons in hippocampus at the CA3 region in β-thalassaemia mice. Cognitive impairment in β-thalassaemia mice was significantly correlated with several intrinsic β-thalassaemic factors including iron overload, anaemia, damaged red blood cells (RBCs), phosphatidylserine (PS)-exposed RBC large extracellular vesicles (EVs) and PS-exposed medium EVs. This highlights the importance of blood transfusion and iron chelation in β-thalassaemia patients. In addition, to improve patients' quality of life, assessment of cognitive functions should become part of routine follow-up.

Protocol guide for food foraging behavior test: Assessment of decision making in rodents

Food foraging behavior requires higher cognitive function like investing efforts in decision making. Hoarding food for the future consumption in adverse climatic conditions or to avoid predatory threats needs precise perception and potential of decision making to overcome challenges in the time of need. The brain areas and neural circuitry responsible for such cognitive skills are poorly understood. Previously available animal models are trained prior to test, which makes it difficult to understand the true nature of animals, and hoard the food from external source into the cage. The new food foraging behavior test, recently developed and evidenced by Li et al., relies on untrained rats and test the competitive ability and hoarding from source within the test box. It can be used to study decision making potentials and underlying neural bases in laboratory settings. Multiple aspects like food quality/flavor preference, competitive nature can be assessed within the test box and the paradigm is conveniently customizable according the hypothesis. However, a detailed protocol guide, to be followed in the laboratory setting, for food foraging behavior test is not available. Therefore, it is urged to produce an elaborated guide for scientists to conduct food foraging behavior test in convenient and precise manner.

Targeted ablation of signal transducer and activator of transduction 1 alleviates inflammation by microglia/macrophages and promotes long-term recovery after ischemic stroke

BACKGROUND

Brain microglia and macrophages (Mi/MΦ) can shift to a harmful or advantageous phenotype following an ischemic stroke. Identification of key molecules that regulate the transformation of resting Mi/MΦ could aid in the development of innovative therapies for ischemic stroke. The transcription factor signal transducer and activator of transduction 1 (STAT1) has been found to contribute to acute neuronal death (in the first 24 h) following ischemic stroke, but its effects on Mi/MΦ and influence on long-term stroke outcomes have yet to be determined.

METHODS

We generated mice with tamoxifen-induced, Mi/MΦ-specific knockout (mKO) of STAT1 driven by Cx3cr1^CreER. Expression of STAT1 was examined in the brain by flow cytometry and RNA sequencing after ischemic stroke induced by transient middle cerebral artery occlusion (MCAO). The impact of STAT1 mKO on neuronal cell death, Mi/MΦ phenotype, and brain inflammation profiles were examined 3-5 days after MCAO. Neurological deficits and the integrity of gray and white matter were assessed for 5 weeks after MCAO by various neurobehavioral tests and immunohistochemistry.

RESULTS

STAT1 was activated in Mi/MΦ at the subacute stage (3 days) after MCAO. Selective deletion of STAT1 in Mi/MΦ did not alter neuronal cell death or infarct size at 24 h after MCAO, but attenuated Mi/MΦ release of high mobility group box 1 and increased arginase 1-producing Mi/MΦ 3d after MCAO, suggesting boosted inflammation-resolving responses of Mi/MΦ. As a result, STAT1 mKO mice had mitigated brain inflammation at the subacute stage after MCAO and less white matter injury in the long term. Importantly, STAT1 mKO was sufficient to improve functional recovery for at least 5 weeks after MCAO in both male and female mice.

CONCLUSIONS

Mi/MΦ-targeted STAT1 KO does not provide immediate neuroprotection but augments inflammation-resolving actions of Mi/MΦ, thereby facilitating long-term functional recovery after stroke. STAT1 is, therefore, a promising therapeutic target to harness beneficial Mi/MΦ responses and improve long-term outcomes after ischemic stroke.

Peroxiredoxin-3 plays a neuroprotective role in early brain injury after experimental subarachnoid hemorrhage in rats

Subarachnoid hemorrhage (SAH), a type of hemorrhagic stroke, is a neurological emergency associated with a high morbidity and mortality rate. After SAH, early brain injury (EBI) is the leading cause of poor prognosis in SAH patients. Peroxiredoxins (PRDXs) are a family of sulphhydryl-dependent peroxidases. Peroxiredoxin-3 (PRDX3) is mainly located in the mitochondria of neurons, which can remove hydrogen peroxide (H2O2); however, the effect of PRDX3 on EBI after SAH remains unclear. In this study, an endovascular perforation model was used to mimic SAH in Sprague Dawley rats in vivo. The results revealed that after SAH, PRDX3 levels decreased in the neurons. PRDX3 overexpression by neuron-specific adeno-associated viruses upregulated PRDX3 levels. Furthermore, PRDX3 overexpression improved long- and short-term behavioral outcomes and alleviated neuronal impairment in rats. Nissl staining revealed that the upregulation of PRDX3 promoted cortical neuron survival. PRDX3 overexpression decreased the H2O2 content and downregulated caspase-9 expression. In conclusion, PRDX3 participates in neuronal protection by inhibiting the neuronal mitochondria-mediated death pathway; PRDX3 may be an important target for EBI intervention after SAH.

Comparison of young male mice of two different strains (C57BL/6J and the hybrid B6129SF1/J) in selected behavior tests: a small scale study

Background

All mouse strains are different, before choosing a strain for a large study, a small scale study should be done. In this study, we compared young males of two mouse strains, C57BL/6J and the hybrid B6129SF1/J, and gained knowledge on their performance in three different behavioral tests; open field (OF) test, Barnes maze (BM) test and a restraint stress test.

Results

We found that the young males of the C57BL/6J strain spent more time moving in the OF. In the BM, the hybrid covered less ground before reaching the goal box during the first three sessions, than the C57BL/6J. The hybrid left more fecal pellets than C57BL/6J both in OF and BM. During the stress test, the C57BL/6J had a lower corticosterone response than the hybrid.

Conclusions

Our findings indicate that the C57BL/6J has a presumably higher locomotor activity and/or explorative behavior than the hybrid, while the hybrid appeared more sensitive to stress.

[Effects of CACNA1H gene knockout on autistic-like behaviors and the morphology of hippocampal neurons in mice]

OBJECTIVE

To investigate the effects of CACNA1H gene knockout (KO) on autistic-like behaviors and the morphology of hippocampal neurons in mice.

METHODS

In the study, 25 CACNA1H KO mice of 3-4 weeks old and C57BL/6 background were recruited as the experimental group, and 26 wild type (WT) mice of the same age and background were recruited as the control group. Three-chamber test and open field test were used to observe the social interaction, anxiety, and repetitive behaviors in mice. After that, their brain weight and size were measured, and the number of hippocampal neurons were observed by Nissl staining. Furthermore, the CACNA1H heterozygote mice were interbred with Thy1-GFP-O mice to generate CACNA1H^-/--Thy1⁺(KO-GFP) and CACNA1H^+/+-Thy1⁺ (WT-GFP) mice. The density and maturity of dendritic spines of hippocampal neurons were observed.

RESULTS

In the sociability test session of the three-chamber test, the KO mice spent more time in the chamber of the stranger mice than in the object one (F_{1, 14}=95.086, P < 0.05; Post-Hoc: P < 0.05), without any significant difference for the explored preference index between the two groups (t=1.044, P>0.05). However, in the social novelty recognition test session, no difference was observed between the time of the KO mice spend in the chamber of new stranger mice and the stranger one (F_{1, 14}=18.062, P < 0.05; Post-Hoc: P>0.05), and the explored preference index of the KO mice was less than that of the control group (t=2.390, P < 0.05). In the open field test, the KO mice spent less time in the center of the open field apparatus than the control group (t=2.503, P < 0.05), but the self-grooming time was significantly increased compared with the control group (t=-2.299, P < 0.05). Morphological results showed that the brain weight/body weight ratio (t=0.356, P>0.05) and brain size (t=-0.660, P>0.05) of the KO mice were not significantly different from those of the control group, but the number of neurons were significantly reduced in hippocampal dentate gyrus compared with the control group (t=2.323, P < 0.05). Moreover, the density of dendritic spine of dentate gyrus neurons in the KO-GFP mice was significantly increased compared with the control group (t=-2.374, P < 0.05), without any significant difference in spine maturity (t=-1.935, P>0.05).

CONCLUSION

CACNA1H KO mice represent autistic-like behavior, which may be related to the decrease in the number of neurons and the increase in the density of dendritic spine in the dentate gyrus.

Dynamic weight-bearing test during jumping: A sensitive outcome measure of chronic osteoarthritis pain in rats

Pain due to osteoarthritis (OA) often occurs during locomotion in the vertical direction when joints are subjected to high mechanical load, e.g. during standing up from a chair or using stairs. To investigate joint pain in OA rat models, dynamic weight-bearing or gait analysis is traditionally conducted during horizontal walking on a flat surface. However, in chronic models of OA, which are of particular translational relevance for the disease, differences in the readouts between OA and control rats are often weak and of high variability leading to an insufficient assay window for drug profiling. To measure pain-related symptoms more sensitively, we conducted a dynamic weight-bearing test in the moment of a strong voluntary mechanical load. For that, we permanently housed rats in a four-story rat colony cage (RCC) and determined hind paw forces during voluntary jumping from one level to the next. This outcome measure was named jump incapacitance. After inducing OA by destabilizing the medial meniscus (DMM), we found that during jumps the average ipsilateral over contralateral hind paw forces were significantly reduced compared with healthy controls (jump incapacitance) from early- (day 7) to late-stage disease (day 90). An intra-articular injection of Zilretta (triamcinolone acetonide extended-release injectable suspension) attenuated OA-induced jump incapacitance after 8 days compared with DMM rats receiving vehicle (p = 0.069). In contrast, a CatWalk test for gait disturbance failed to detect any significant alterations in the chronic course of the DMM model. In conclusion, the dynamic weight-bearing test during jumping represents a novel method to characterize joint pain symptoms even in a slowly progressive OA rat model. It is sensitive, observer independent, relates to clinically relevant endpoints and demonstrates backtranslation of a drug that is approved for the treatment of OA knee pain.

Exercise preconditioning ameliorates cognitive impairment and anxiety-like behavior via regulation of dopamine in ischemia rats

Cognitive impairment and anxiety are common health problems in acute ischemic stroke patients. Meanwhile, dopamine in the striatal brain region is significantly increased during the acute phase of cerebral ischemia. Besides, the studies shown that striatum and change of striatal dopamine are associated with learning and memory and anxiety. Further, physical exercise has been shown to improve neurocognitive and emotional function in animal models and patients with cerebral ischemia. However, the exact mechanism underlying this effect is unclear. The purpose of this research is to explore the effect of pre-ischemic voluntary wheel running on levels of striatal dopamine, cognition and anxiety in cerebral ischemia rats.

METHODS

48 adult male Sprague-Dawley rats were enrolled in this study and divided randomly in following 6 groups: sham group (S group, n = 8), ischemia group (I group, n = 8), 1 week wheel running group (1R group), 4 weeks wheel running group (4R group), 1 week pre-ischemia wheel running group (1RI group, n = 8) and 4 weeks pre-ischemia wheel running group (4RI group, n = 8). After training, cerebral ischemia was induced by permanent bilateral common carotid artery ligation (2-VO) operation. Microdialysis was used to collect dialysates from the striatum immediately from 30 min before ischemia to 90 min after ischemia. High-performance liquid chromatography-electrochemical detection system (HPLC) was used to determine the content of dopamine in the dialysates. Passive avoidance and elevated plus maze test were used to test neurocognitive function 24 h after 2-VO cerebral ischemia.

RESULTS

As compare with the constant striatal dopamine level of S group, the striatal dopamine level in I group after ischemia showed a trend of rapid increasing and reached maximum value at the 20 min (P<0.001), then decreased gradually. The striatal dopamine level in 1RI and 4RI group showed the trend were similar to I group, but the increasing magnitude was attenuated. A comparison of the basal striatal dopamine level in 4 groups found that the basal dopamine level in 1RI and 4RI group were higher than S and I group (P<0.001). In passive avoidance task, the retention latency of I group was significantly shorter than S group (P<0.001), and the retention latency of the 1RI, 1R and 4R, 4RI group were longer than I group (P<0.001), there was no significant difference in S, 1RI, 1R, 4R and 4RI group (P>0.05). In elevated plus maze test, the time and entrance numbers of open arms in I group were significantly less than S group (P<0.05), but these indices were no significant difference in S, 1RI, 1R, 4RI and 4RI group.

CONCLUSION

According to our results, 1 or 4 weeks pre-ischemia wheel running can significantly increase the basal dopamine level, attenuate the increase of striatal dopamine induced by cerebral ischemia and improve neurocognitive function in ischemia rats.

The effect of some natural antioxidants against cisplatin-induced neurotoxicity in rats: behavioral testing

Background

Cisplatin (CP) is a common antineoplastic agent widely used to treat a broad spectrum of cancers. However, its usage for cancer treatment was restricted due to various side effects such as neurotoxicity, nephrotoxicity, hepatotoxicity and ototoxicity. Neurotoxicity in patients who have undergone a complete course of chemotherapy is clinically evident. CP administration caused problems in rats with memory and learning.

Methods

The effect of combination of CP with either thymoquinone (TQ) or geraniol (Ger) on cell viability of human breast cancer cells (MCF-7) was detected by MTT assay. Forty male Wistar albino rats, healthy and adult, were divided into four groups: normal control, CP-treated group, CP + TQ-treated group and CP + Ger-treated group.

Results

Our results demonstrated that prophylactic treatment with either TQ or Ger plus CP enhanced the anticancer effect of CP in MCF-7 cell line. In vivo study showed that CP-treated rats had higher depressives like behavior in open field and Morris water maze test while prophylactic treatment with either TQ or Ger and CP significantly enhanced the performance of depressive-like behavior. Also, histopathological evaluation of brain tissues proved the neurotoxic effect of CP and the possible protective activity of either TQ or Ger.

Conclusion

The findings of the present work revealed that TQ or Ger along with CP may enhance the antitumor effect of CP. Also, spontaneous administration of CP with either TQ or Ger as natural antioxidants may prevent CP-induced neurotoxicity in rats through diminishing the memory and learning impairment.

Long-term Therapeutic Effects of Extracorporeal Shock Wave-Assisted Melatonin Therapy on Mononeuropathic Pain in Rats

We evaluated the ability of extracorporeal shock wave (ECSW)-assisted melatonin (Mel) therapy to offer an additional benefit for alleviating the neuropathic pain (NP) in rats. Left sciatic nerve was subjected to chronic constriction injury (CCI) to induce NP. Animals (n = 30) were randomized into group 1 (sham-operated control), group 2 (CCI only), group 3 (CCI + ECSW), group 4 (CCI + Mel) and group 5 (CCI + ECSW + Mel). By days 15, 22 and 29 after CCI, the thermal paw withdrawal latency (TPWL) and mechanical paw withdrawal threshold (MPWT) were highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, but they showed no difference between the later two groups (all p < 0.0001). The protein expressions of inflammatory (TNF-α, NF-κB, MMP-9, IL-1ß), oxidative-stress (NOXs-1, -2, -4, oxidized protein), apoptotic (cleaved-caspase3, cleaved-PARP), DNA/mitochondrial-damaged (γ-H2AX/cytosolic-cytochrome C), microglia/astrocyte activation (ox42/GFAP), and MAPKs [phosphorylated (p)-p38, p-JNK, p-ERK] biomarkers in dorsal root ganglia neurons (DRGs) and in spinal dorsal horn were exhibited an opposite pattern of TPWL among the five groups (all p < 0.0001). Additionally, protein expressions of Nav.1.3, Nav.1.8 and Nav.1.9 in sciatic nerve exhibited an identical pattern to inflammation among the five groups (all p < 0.0001). The numbers of cellular expressions of MAPKs (p-ERK1/2+/peripherin + cells, p-ERK1/2+/NF200 + cells and p-JNK+/peripherin + cells, p-JNK+/NF200 + cells) and voltage-gated sodium channels (Nav.1.8+/peripherin + cells, Nav.1.8+/NF200 + cells, Nav.1.9+/peripherin + cells, Nav.1.9+/NF200 + cells) in small and large DRGs displayed an identical pattern to inflammation among the five groups (all p < 0.0001). In conclusion, the synergistic effect of combined ECSW-Mel therapy is superior to either one alone for long-term improvement of mononeuropathic pain-induced by CCI in rats.

Effects of Tianeptine on Adult Rats Following Prenatal Stress

Objective

Exposing a pregnant female to stress during the critical period of embryonic fetal brain development increases the risk of psychiatric disorders in the offspring. The objective of this study was to investigate the effect of antidepressant tianeptine on prenatally stressed (PNS) rats.

Methods

In this study, a repeated variable stress paradigm was applied to pregnant rats during the last week of gestation. To investigate the effects of antidepressant tianeptine on PNS rats, behavioral and protein expression analyses were performed. Forced swim test, open field test, and social interaction test were performed to determine changes in PNS rats compared to non-stressed offspring. Haloperidol was used as a positive control as an antipsychotic drug based on previous studies.

Results

Behavioral changes were restored after treatment with tianeptine or haloperidol. Western blot and immunohistochemical analyses of the prefrontal cortex revealed downregulation of several neurodevelopmental proteins in PNS rats. After treatment with tianeptine or haloperidol, their expression levels were increased.

Conclusion

Downregulation of several proteins in PNS rats might have caused subsequent behavioral changes in PNS rats. After tianeptine or haloperidol treatment, behavioral changes in PNS rats were restored. Therefore, tianeptine might decrease incidence of prenatal stress related-psychiatric disorders such as depression and schizophrenia.

Melatonin produces a rapid onset and prolonged efficacy in reducing depression-like behaviors in adult rats exposed to chronic unpredictable mild stress

The present study was aimed at evaluating the rapidity and duration of melatonin as an antidepressant in a rat model of depression. The rats were subjected to a six-week period of unpredictable mild stress followed by melatonin treatment. Three groups of rats were included in this study: Controls (CON - no stress exposure), Chronic Unpredictable Mild Stress (CUS) and CUS followed by melatonin (MT). Stressors consisted of exposure to rotation on a shaker, placement in a chamber maintained at 4°C, lights off for 3h, lights on overnight, exposure to an aversive odor, 45° tilted cages, food and water deprivation and crowding and isolated housing. Subsequently, the saline vehicle (CUS) or melatonin was administered at a dose of 10mg/kg for 14days period. Body weight and behavioral tests were used to evaluate depression-like behavior and its recovery following melatonin treatment. While body weight increases were significantly lower in rats exposed to CUS versus CON, body weights of the MT group increased significantly following melatonin treatment as compared with the CUS group. With regard to results obtained with behavioral assays indicative of depression, rapid and long-term functional recoveries in depression were observed in the MT as compared to the CUS group. The results indicate that not only does melatonin induce an antidepressant-like action within this rat model of depression, but does so with a rapid onset and prolonged efficacy. As most current treatments for depression require an extended period of administration, our current results suggest that melatonin may prove to be a particularly effect agent to promote a rapid onset and prolonged behavioral benefits in the treatment of depression.

Pin1 Knockout Mice: A Model for the Study of Tau Pathology in Alzheimer's Disease

Pin1 knockout in mice causes age-dependent neuropathy characterized by motor and behavioral deficits, tau hyper phosphorylation, tau filament formation, and neuronal degradation. Here, we describe the methods with mouse behavior test, immunostaining, and immunoblotting to detect many aspects of neurodegeneration in Pin1 knockout mice.

Overexpression of serum amyloid a 1 induces depressive-like behavior in mice

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by loss of memory and cognitive abilities. In AD, amyloid β (Aβ) protein aggregates in the brain of patients, forming amyloid plaques. Aβ plaques are known to be surrounded by activated microglial cells. Serum amyloid A (SAA) is elevated from several hundred to 1000-fold as part of the immune response against various injuries, including trauma, infection, and inflammation. Additionally, continuous elevation of SAA is related to the development of amyloidosis. This study was designed to identify the relationship between SAA1 and AD using liver specific SAA1 overexpressing mice (TG), because SAA1 is expressed in the liver during the acute phase. We detected exogenous SAA1 expression in the brain of TG mice. This result implies that liver-derived SAA1 migrates to the brain tissues. Thus, we confirmed that the blood brain barrier (BBB) functioned normally using Evans-blue staining and CARS. Furthermore, our results show an increase in the accumulation of the 87kDa form of Aβ in TG mice compared to wild type mice (WT). Additionally, the number of microglial cells and levels of pro-inflammatory cytokines were increased. Next, we investigated the relationship between SAA1 and depression by performing social interaction tests. The results showed that TG mice have a tendency to avoid stranger mice and an impaired social recognition. In conclusion, the SAA1 TG mouse model is a valuable model to study depression.

Effect of chronic social defeat stress on behaviors and dopamine receptor in adult mice

Victims of bullying often undergo depression, low self-esteem, high anxiety and post-traumatic stress disorder symptoms. The social defeat model has become widely accepted for studying experimental animal behavior changes associated with bullying; however, differences in the effects in susceptible and unsusceptible individuals have not been well studied. The present study investigated the effects of social defeat stress on behavior and the expression of dopamine receptors D1 and D2 in the brains of adult mice. Adult mice were divided into susceptible and unsusceptible groups after 10days of social defeat stress. Behavioral tests were conducted, and protein levels in the brains were assessed by Western blotting. The results indicate that all mice undergo decreased locomotion and increased anxiety behavior. However, decreased social interaction and impaired memory performance were only observed in susceptible mice. A significantly decreased expression of D1 was observed in the prefrontal cortex and amygdala of susceptible mice only. No significant differences in D2 expression were shown between control and defeated mice in any area studied. These data indicate that depression-like behavior and cognition impairment caused by social defeat stress in susceptible mice may be related to changes in the dopamine receptor D1.