Chronic N-Acetylcysteine Treatment Prevents Amphetamine-Induced Hyperactivity in Heterozygous Disc1 Mutant Mice, a Putative Prodromal Schizophrenia Animal Model.

Symptoms of schizophrenia (SZ) typically emerge during adolescence to young adulthood, which gives a window before full-blown psychosis for early intervention. Strategies for preventing the conversion from the prodromal phase to the psychotic phase are warranted. Heterozygous (Het) Disc1 mutant mice are considered a prodromal model of SZ, suitable for studying psychotic conversion. We evaluated the preventive effect of chronic N-acetylcysteine (NAC) administration, covering the prenatal era to adulthood, on the reaction following the Amph challenge, which mimics the outbreak or conversion of psychosis, in adult Het Disc1 mice. Biochemical and morphological features were examined in the striatum of NAC-treated mice. Chronic NAC treatment normalized the Amph-induced activity in the Het Disc1 mice. Furthermore, the striatal phenotypes of Het Disc1 mice were rescued by NAC including dopamine receptors, the expression of GSK3s, MSN dendritic impairments, and striatal PV density. The current study demonstrated a potent preventive effect of chronic NAC treatment in Disc1 Het mice on the acute Amph test, which mimics the outbreak of psychosis. Our findings not only support the benefit of NAC as a dietary supplement for SZ prodromes, but also advance our knowledge of striatal dopamine receptors, PV neurons, and GSK3 signaling pathways as therapeutic targets for treating or preventing the pathogenesis of mental disorders.

Behavioral and neurochemical changes induced by repetitive combined treatments of ketamine and amphetamine in mice.

The combined abuse of recreational drugs such as ketamine (Ket) and amphetamine (Amph) should be seriously considered important social and health issues. Numerous studies have documented the behavioral and neurochemical changes associated with polydrug administration; however, most studies have only examined the acute effects. The consequences following chronic repetitive polydrug use are less studied. In the present study, intraperitoneal injections of saline, Amph (5 mg/kg), low dose Ket (LK, 10 mg/kg), high dose Ket (HK, 50 mg/kg), or Amph plus LK or HK (ALK or AHK) were conducted twice a day for three consecutive days, and one final treatment was administered on day 4. After seven total treatments, animal behaviors, including locomotion, stereotypy and ataxia, were examined in a novel open field. The expression of GAD67 and dopamine (DA) levels were assessed in the striatum and motor-related cortices using immunohistochemistry and high-performance liquid chromatography. Drug-induced hyperactivities and Amph-mediated potentiation of Ket-triggered ataxia manifested after repeated drug treatments. A significant increase in the number of GAD67-positive puncta in the striatum and motor-related cortices was observed, suggesting a neural adaptive change in the GABAergic system. Four hours after the final treatment, while the behavioral hyperactivities had ceased, considerable changes were still evident in the motor-related cortices, suggesting modulation to the DAergic system. Together, our results show the interactive effects of these two drugs in behavioral and neurochemical aspects and neural adaptive changes in the GABAergic and DAergic systems.

Exploring the impact of culture techniques and patient demographics on the success rate of primary culture of human periodontal ligament stem cells.

Background/purpose: Periodontal ligament stem cells (PDLSCs) have the potential for regenerating periodontal tissue. The study aims to investigate the impact of demographics (ages, gender, disease) and culture techniques (shipping storage time and culture method) on the success of primary culture. Materials and methods: PDLSCs were collected from 51 teeth of 26 patients and cultured via outgrowth (OG) and enzymatic digestion (ED) methods. Cells characteristics were confirmed by flow cytometry, MTT, and ARS. The primary culture success rate was evaluated with a serial chi-square test to determine the relationship with culture technique (ED/OG and ≤4 h/prolonged culture) and patient demographics (Young/Old, Female/Male, and Health/Periodontitis). Results: The overall success rate of Health group (69.7%) was higher than Periodontitis (38.9%). Culturing within 4 h possessed a higher success rate (71.8%) than prolonged group (16.7%) regardless of patient demographics, and using OG method (81.5%) revealed more promising. Subgroup analysis of 39 cases (culture within 4 h) found that the success rate of OG was higher than ED in the Old group (87.5%-25.0%) and in the Periodontitis group (83.3%-25.0%). Conclusion: Primary culturing of PDLSCs within 4 h and using the outgrowth method led to higher success rates regardless of patient demographics. It can achieve successful PDLSCs culture of older patients or patients with periodontal disease by appropriate culture technique.

Collagen Scaffolds Laden with Human Periodontal Ligament Fibroblasts Promote Periodontal Regeneration in SD Rat Model.

Periodontitis, a chronic inflammatory disease caused by microbial communities carrying pathogens, leads to the loss of tooth-supporting tissues and is a significant contributor to tooth loss. This study aims to develop a novel injectable cell-laden hydrogel consisted of collagen (COL), riboflavin, and a dental light-emitting diode (LED) photo-cross-linking process for periodontal regeneration. Utilizing α-SMA and ALP immunofluorescence markers, we confirmed the differentiation of human periodontal ligament fibroblasts (HPLFs) into myofibroblasts and preosteoblasts within collagen scaffolds in vitro. Twenty-four rats with three-wall artificial periodontal defects were divided into four groups, Blank, COL_LED, COL_HPLF, and COL_HPLF_LED, and histomorphometrically assessed after 6 weeks. Notably, the COL_HPLF_LED group showed less relative epithelial downgrowth (p < 0.01 for Blank, p < 0.05 for COL_LED and COL_HPLF), and the relative residual bone defect was significantly reduced in the COL_HPLF_LED group compared to the Blank and the COL_LED group (p < 0.05). The results indicated that LED photo-cross-linking collagen scaffolds possess sufficient strength to withstand the forces of surgical process and biting, providing support for HPLF cells embedded within them. The secretion of cells is suggested to promote the repair of adjacent tissues, including well-oriented periodontal ligament and alveolar bone regeneration. The approach developed in this study demonstrates clinical feasibility and holds promise for achieving both functional and structural regeneration of periodontal defects.

Characterization of striatal phenotypes in heterozygous Disc1 mutant mice, a model of haploinsufficiency.

Disrupted-in-Schizophrenia 1 (DISC1) is a susceptibility gene for several psychiatric illnesses. To study the pathogenesis of these disorders, we generated Disc1 mutant mice by introducing the 129S6/SvEv 25-bp deletion Disc1 variants into the C57BL/6J strain. In this study, we used heterozygous Disc1 mutant (Het) mice to evaluate the DISC1 haploinsufficiency model of schizophrenia. No changes in locomotor behaviors were observed in Het mice; however, after amphetamine injection, greater locomotor activity was observed in Het mice compared with wild-type (WT) mice. Moreover, amphetamine-induced elevations of c-Fos expression and dopamine level in the striatum were greater in Het mice than in WT controls, suggesting an altered dopaminergic regulation in the striatum of Het mice. Compared with those in WTs, the striatal protein levels of dopamine transporter and D2 dopamine receptor were increased in Het mice, while D1 dopamine receptor level was decreased. DISC1 interacting proteins, GSK3α and GSK3ß, were downregulated in Het mice, whereas the levels of PDE4B and CREB were not altered. Morphologically, the complexities of striatal median spiny neurons (MSNs), parvalbumin-positive interneurons and Iba1-positive microglia were all decreased in Het mice. The density and head diameter of dendritic spines in the MSNs of Het mice were also reduced. Our results indicate that mice lacking one WT Disc1 allele are more sensitive to psychostimulant amphetamine challenge, which might be attributed to the altered structure and function of the striatal dopaminergic system. Here, we demonstrated striatal phenotypes in heterozygous Disc1 mutant mice, which could be a promising model of DISC1 haploinsufficiency.

Combinational effects of ketamine and amphetamine on behaviors and neurotransmitter systems of mice.

The combined ingestion of ketamine (Ket) and amphetamine (Amph) by drug-users has been rampant and produced more severe behavioral abnormality. However, the interactive consequences of the two drugs are still unclear. In this study, we treated adult male mice with a single i.p. injection of saline, Amph (5 mg/kg), low Ket (LK, 10 mg/kg), high Ket (HK, 50 mg/kg), or Amph and LK or HK (ALK or AHK) and examined their behavioral and neurochemical changes at 0.5 and 2 h post-injection. Compared with saline, Amph, LK or HK treatment alone increased the levels of motor activities such as locomotion, stereotypy or ataxia of mice. Notably, at combined treatments, LK and HK differentially exacerbated Amph-induced locomotion and stereotypy, whereas Amph worsened LK or HK-produced ataxia. The higher striatal dopamine levels of A, ALK and AHK groups correlated with their greater motor activities. The prolonged increase of dopamine in the motor cortex of ALK and AHK mice may associate with the longer duration of behavioral hyperactivity and greater peak score of locomotion; the greater dopamine level in the somatosensory cortex probably contributes to the more severe ataxia. Furthermore, in the striatum of all drug-treated groups, the expression of GAD67 mRNA and GAD67-positive punctates was higher than respective saline controls, indicating the involvement of GABAergic system in the drug-induced behavioral changes. Our results demonstrate the acute interplay between Amph and Ket in both behavioral and neurochemical aspects for the first time. Dopaminergic and GABAergic systems were affected differentially by the drugs in the striatum.

Amphetamine differentially modifies the expression of monoaminergic and GABAergic synaptic boutons and processes in lateral habenula, dorsal and ventral hippocampal formation.

The habenular complex is thought to be associated with cognitive functions and indirectly connected with the hippocampal formation (HF). Thus the responses of the monoaminergic and GABAergic neurons were examined in both structures to the psychostimulant, amphetamine (Amph). Immunocytochemical analysis was performed on brain sections prepared from adult mice treated with a single or multiple (2 doses/day, 7 doses in total) injections of saline or Amph, 5mg/kg. The synaptic boutons were verified by immuno-electron microscopy specific for parvalbumin (PV), glutamic acid decarboxylase(67) (GAD(67)), aromatic amino acid decarboxylase (AADC) or dopamine-ß-hydroxylase (DBH). In the lateral part of the lateral habenula (LHb), at 4h post-acute Amph, the densities of PV-positive boutons/processes and DBH-boutons were decreased by approximate 75% and 72% respectively, compared with corresponding saline-controls; however, at 4h post-repeated Amph exposure, PV was increased by 244%, and DBH unaltered. In the dorsal HF (DHF), at 4h post-repeated Amph exposure, GAD(67)-boutons and PV resembled controls in CA1 and CA3 pyramidal cell layers, whereas in the granule cell layer of dentate gyrus (DG), PV was increased by 112%, and GAD(67) unchanged. As shown by biochemical methods, at 4h post-repeated Amph, the decreased level of DHF GABA probably correlates with the immunocytochemical changes. In the ventral HF (VHF), at 4h post-repeated Amph treatment, PV and the enzymes of CA1 and DG were unaltered, while CA3 PV was decreased by 63%, and AADC-boutons increased 55%. Double immuno-electron microscopy revealed synaptic contacts between PV and GAD(67) containing presynaptic or postsynaptic elements, and between PV or GAD(67) and DBH or AADC. This ultrastructural evidence may support the functional significance of the Amph-induced differential changes, which could reflect Amph toxicity and distinct characteristics of the LHb, DHF and VHF.

Differential changes in cerebellar transmitter content and expression of calcium binding proteins and transcription factors in mouse administered with amphetamine.

Cerebellar mechanisms were explored underlying the effects of amphetamine (Amph) on the brain, by monitoring primarily the neurochemistry of the cerebellum. Adult mice received repeated intermittent injections of d-Amph, 5mg/kg or saline, twice daily for three days and once on day 4. As revealed by the biochemical analysis, the levels of GABA content were increased by 68-93% in the cerebellar vermis and hemisphere of mice at 4h after the first (acute) or the last (repeated) Amph injections, though the glutamate content was unaltered, compared to the respective saline-treated controls. By contrast, at 4h post-repeated Amph, in the vermis, the level of norepinephrine was approximate 38% lower than the corresponding control and 5-hydroxytryptamine (5-HT) resembled the control, whereas in the hemisphere, the norepinephrine content was similar to control and 5-HT 66% higher, implying cerebellar lobe-dependent changes. However, in both lobes, at 4h after the acute and repeated Amph exposures, changes of the transmitter content were correlated with reductions of 50-64% in the levels of the phosphorylated (p) MAP kinase (K) expression and 39-55% in the calbindin-D28k (CB) of the Purkinje cell somata, and increases of 289-556% in pCREB, 373-594% c-FOS, and 51-76% calretinin of the granular layer, as shown by immunohistochemical analysis. The up-regulated GABA content in the vermis and hemisphere may be associated with the decreased expression of Purkinje somatal CB and pMAPK, implicating a relation between the Ca(2+) of Purkinje cells and the level of GABA. Furthermore, the prominent increases of the granular layer pCREB, c-FOS and calretinin may influence the activity of Purkinje cells, which are known to be modulated by the granule cells. The data indicate that the Amph exposure selectively alters specific transmitters in the cerebellar lobes and modifies the cellular expression of distinct signaling proteins in the cerebellar layers.