An impedance based microfluidic sensor for evaluation of individual red blood cell solute permeability.

-In this paper, we investigate a microfluidic based sensing device for cell membrane permeability measurements in real time with applications in rapid assessment of red blood cell (RBC) quality at the individual cell level. The microfluidic chip was designed with unique abilities to line up the RBCs in the centerline of the microchannel using positive dielectrophoresis (p-DEP) forces, rapid mixing of RBCs with various media (e.g.

Effects of CO₂ Euthanasia of C57BL/6 Mice on Sperm Motility, In Vitro Fertilization, and Embryonic Developmental Competence.

Cryopreservation of epididymal sperm collected after euthanasia is a common method to preserve and distribute valuable mouse models worldwide. However, the euthanasia method used prior to sperm collection must not adversely affect sperm quality. The most common method of euthanasia in mice is CO₂ asphyxiation, but its effect on the quality of sperm collected postmortem is largely unknown.

Microglial Inflammation and Cognitive Dysfunction in Comorbid Rat Models of Striatal Ischemic Stroke and Alzheimer's Disease: Effects of Antioxidant Catalase-SKL on Behavioral and Cellular Pathology.

Ischemic stroke often co-occurs with Alzheimer's disease (AD) leading to a worsened clinical outcome. Neuroinflammation is a critical process implicated in AD and ischemic pathology, associated with cognitive decline. We sought to investigate the combined effects of ischemic stroke induced by endothelin-1 injection in two AD rat models, using motor function, memory and microglial inflammation in the basal forebrain and striatum as readouts.

Precocious White Matter Inflammation and Behavioural Inflexibility Precede Learning and Memory Impairment in the TgAPP21 Rat Model of Alzheimer Disease.

Neuroinflammation and behavioural inflexibility are both common in late adulthood but far more profound in Alzheimer disease (AD). To investigate the relationship between ageing, AD, neuroinflammation, and behavioural flexibility, male wild-type Fischer 344 (Wt) and the transgenic APP21 (TgAPP21) rats were aged to 4, 8, 13, and 22 months and evaluated for neuroinflammation and cognitive impairment. TgAPP21 rats overexpress a pathogenic variant of the human amyloid precursor protein (hAPP; Swedish and Indiana mutations) but do not spontaneously develop overt pathology related to AD.

Cryopreservation and Transplantation of Laboratory Rodent Ovarian Tissue for Genome Banking and Biomedical Research.

Genetic modifications in combination with highly sophisticated assisted reproductive technologies such as in vitro oocyte maturation and development, in vitro fertilization, intracytoplasmic sperm injection, and in vitro embryo culture have opened many research avenues and treatment options for both animals and humans. The number of genetically modified (GM) rodent strains increased considerably during the last several decades, and their numbers are expected to increase due to efficient gene editing technologies including the CRISPR/Cas9. Rodent ovarian tissues (OT) cryopreservation and transplantation procedures have several applications in biomedical field: they provide a fertility restoration option for GM rodent strains in some circumstances.

Cryopreservation of Mouse Sperm for Genome Banking.

Germplasm cryobanking of transgenic rodent models is a valuable tool for protecting important genotypes from genetic drift, genetic contamination, and loss of breeding colonies due to disease or catastrophic disasters to the housing facilities as well as avoiding stress associated with domestic and international live animal shipment. Furthermore, cryopreservation of germplasm enhances management efficiencies by saving animal room space, reducing workload for staff, reducing cost of maintaining live animals, reducing the number of animals used to maintain a breeding colony, and facilitating transportation of genetics by allowing distribution of frozen germplasm rather than live animals which also reduces the risk of transfer of pathogens between facilities. Thus, effective long-term preservation methods of mouse spermatozoa are critical for future reconstitution of scientifically important mouse strains used for biomedical research.

Hypertension and Pathogenic hAPP Independently Induce White Matter Astrocytosis and Cognitive Impairment in the Rat.

Hypertension is recognized as a risk factor for Alzheimer disease, but the causal link remains undetermined. Although astrocytes and microglia play an important role in maintaining the neurovascular unit, astrocytes and microglia have been understudied in comorbid models of hypertension and Alzheimer disease. In this study, male transgenic Fischer 344 rats (TgAPP21) overexpressing a pathogenic human amyloid precursor protein received 8 weeks of Angiotensin II infusion to increase blood pressure, and the rats were evaluated for astrocytosis, microgliosis, and cognitive function.

Morphometric, subcellular, in vitro fertilisation and embryonic developmental assessment of mouse oocytes produced by anti-inhibin serum or pregnant mare serum gonadotrophin superovulation.

This study compared the morphometric, subcellular characteristics, in vitro fertilisation (IVF) and embryonic developmental potential of metaphase II (MII) mouse oocytes obtained from females superovulated with either anti-inhibin serum-human chorionic gonadotrophin (AIS-hCG) or pregnant mare serum gonadotrophin (PMSG)-hCG. The oocyte's quantity, quality, zona pellucida (ZP) thickness, perivitelline space (PVS), diameter, microtubules, F-actin, cortical granules (CGs) and mitochondrial distribution were determined. Superovulation using AIS-hCG resulted in a higher numbers of oocyte/donor compared with PMSG-hCG (P=0.

White matter inflammation and cognitive function in a co-morbid metabolic syndrome and prodromal Alzheimer's disease rat model.

Background: Metabolic syndrome, the development of which is associated with high-caloric Western diet (HCD) intake, represent a risk factor for mild cognitive impairment (MCI) and dementia including Alzheimer's disease (AD) later in life. This study aimed to investigate the effect of diet-induced metabolic disturbances on white matter neuroinflammation and cognitive function in a transgenic (TG) Fischer 344 rat carrying a human β-amyloid precursor protein (APP) gene with Swedish and Indiana mutations (APP21 TG), a model of pre-AD and MCI.

Methods: TG and wildtype (WT) rats received either a HCD with 40% kJ from fat supplemented with 20% corn syrup drink or a standard diet for 12 weeks.

Ovariectomy Influences Cognition and Markers of Alzheimer's Disease.

Alzheimer's disease (AD) is one of the most devastating and costly diseases, and prevalence of AD increases with age. Furthermore, females are twice as likely to suffer from AD compared to males. The cessation of reproductive steroid hormone production during menopause is hypothesized to cause this difference.

Euthanasia via CO inhalation causes premature cortical granule exocytosis in mouse oocytes and influences in vitro fertilization and embryo development.

Generation of high quality mouse metaphase II oocytes is an integral part for efficient in vitro fertilization (IVF), and subsequent embryo production for reproductive studies and genome banking. The main objectives of this study were to investigate the impact of various euthanasia methods on IVF, embryo development, and subcellular structures of MII mouse oocytes. Following superovulation regimen, female mice were euthanized by high flow CO (H CO ), low flow CO (L CO ), or cervical dislocation (CD).

Impaired behavioural flexibility related to white matter microgliosis in the TgAPP21 rat model of Alzheimer disease.

Executive dysfunction and white matter inflammation continue to be relatively understudied in rodent models of Alzheimer's disease (AD). Behavioural inflexibility is an important component of executive dysfunction that can be further categorized as perseverative or regressive, which respectively specify whether maladaptive persistence occurs early or late during a behavioural change. Previous studies of the TgAPP21 rat model of AD (expressing pathogenic hAPP) suggested a potentially spontaneous increase of regressive behavioral inflexibility.

APP21 transgenic rats develop age-dependent cognitive impairment and microglia accumulation within white matter tracts.

Background: Most of the animal models commonly used for preclinical research into Alzheimer's disease (AD) largely fail to address the pathophysiology, including the impact of known risk factors, of the widely diagnosed sporadic form of the disease. Here, we use a transgenic rat (APP21) that does not develop AD-like pathology spontaneously with age, but does develop pathology following vascular stress. To further the potential of this novel rat model as a much-needed pre-clinical animal model of sporadic AD, we characterize APP21 transgenic rats behaviorally and histologically up to 19 months of age.

Memory deficiency, cerebral amyloid angiopathy, and amyloid-β plaques in APP+PS1 double transgenic rat model of Alzheimer's disease.

Transgenic rat models of Alzheimer's disease were used to examine differences in memory and brain histology. Double transgenic female rats (APP+PS1) over-expressing human amyloid precursor protein (APP) and presenilin 1 (PS1) and single transgenic rats (APP21) over-expressing human APP were compared with wild type Fischer rats (WT). The Barnes maze assessed learning and memory and showed that both APP21 and APP+PS1 rats made significantly more errors than the WT rats during the acquisition phase, signifying slower learning.

Membrane-lipid homeostasis in a prodromal rat model of Alzheimer's disease: Characteristic profiles in ganglioside distributions during aging detected using MALDI imaging mass spectrometry.

Background: Accumulation of simple gangliosides GM2 and GM3, and gangliosides with longer long-chain bases (d20:1) have been linked to toxicity and the pathogenesis of Alzheimer's disease (AD). Conversely, complex gangliosides, such as GM1, have been shown to be neuroprotective. Recent evidence using matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS) has demonstrated that a-series gangliosides are differentially altered during normal aging, yet it remains unclear how simple species are shifting relative to complex gangliosides in the prodromal stages of AD.

Bone turnover is altered in transgenic rats overexpressing the P2Y2 purinergic receptor.

It is now widely recognized that purinergic signaling plays an important role in the regulation of bone remodeling. One receptor subtype, which has been suggested to be involved in this regulation, is the P2Y2 receptor (P2Y2R). In the present study, we investigated the effect of P2Y2R overexpression on bone status and bone cell function using a transgenic rat.

Behavioural inflexibility in a comorbid rat model of striatal ischemic injury and mutant hAPP overexpression.

Alzheimer disease (AD) and stroke coexist and interact; yet how they interact is not sufficiently understood. Both AD and basal ganglia stroke can impair behavioural flexibility, which can be reliably modeled in rats using an established operant based set-shifting test. Transgenic Fischer 344-APP21 rats (TgF344) overexpress pathogenic human amyloid precursor protein (hAPP) but do not spontaneously develop overt pathology, hence TgF344 rats can be used to model the effect of vascular injury in the prodromal stages of Alzheimer disease.

Direct Evidence for P2Y2 Receptor Involvement in Vascular Response to Injury.

Objectives: Extracellular nucleotide release at the site of arterial injury mediates the proliferation and migration of vascular smooth muscle cells. Our aim was to investigate the role of the P2Y2 nucleotide receptor (P2Y2R) in neointimal hyperplasia. Approach and Results: Vascular injury was induced by the implantation of a polyethylene cuff around the femoral artery in wild-type and P2Y2R-deficient mice (P2Y2R-/-).

Presenilin 1 transgene addition to amyloid precursor protein overexpressing transgenic rats increases amyloid beta 42 levels and results in loss of memory retention.

Background: We previously reported the production of transgenic rats (APP21 line) that over-express human amyloid precursor protein (APP) containing Swedish and Indiana mutations. In order to generate a better model for Alzheimer's disease (AD), the APP21 rat line was used to generate double transgenic line that over-expressed Presenilin 1 (PS1) with L166P mutation in addition to APP transgene (APP + PS1 line).

Results: Thirty-two double transgenic founders were generated and the ultimate transgenic founder was selected based on PS1 transgene copy number and level of amyloid-beta (Aβ)42 peptide.

Post-thaw ATP supplementation enhances cryoprotective effect of iodixanol in rat spermatozoa.

Background: Successful cryopreservation of rat spermatozoa from various strains still remains a challenge. The objective of this study was to determine if combinations of OptiPrep™ (iodixanol) and adenosine 5'-triphosphate (ATP) can improve rat sperm function during the cryopreservation procedure.

Methods: Epididymal rat spermatozoa were frozen under different OptiPrep™ concentrations (0, 1, 2, 3 or 4 %) and were diluted with media supplemented with or without 2 mM ATP after thawing.

Kaolin-induced chronic hydrocephalus accelerates amyloid deposition and vascular disease in transgenic rats expressing high levels of human APP.

Background: Normal pressure hydrocephalus (NPH) is most common in the elderly and has a high co-morbidity with Alzheimer's disease (AD) and cerebrovascular disease (CVD). To understand the relationship between NPH, AD and CVD, we investigated how chronic hydrocephalus impacts brain amyloid-beta peptide (Aβ) accumulation and vascular pathology in an AD transgenic rodent model. Previously we showed that the altered CSF physiology produced by kaolin-hydrocephalus in older wild-type Sprague-Dawley rats increased Aβ and hyperphosphorylated Tau (Silverberg et.

Molecular and ultrastuctural changes of rat pre-implantation embryos during two-cell developmental arrest.

Background: Rat pre-implantation embryos often suffer 2-cell stage developmental arrest and fail to progress further under in-vitro conditions.

Objective: In order to understand underlying mechanism leading to 2-cell arrest, we investigated the molecular changes, culture conditions and subcellular changes.

Methods: Gene expression in in-vivo developed 2-cell embryos (in-vivo), in- vitro developed 2-cell embryos (in-vitro), and in-vitro 2-cell arrested embryos (arrested) were investigated using microarrays and real-time PCR.

Short-term storage of rat sperm in the presence of various extenders.

Sperm preservation protocols differ among animal species because of different sperm characteristics among species. Rat sperm have extreme sensitivity to suboptimal conditions in centrifugation, pipetting and chilling due to their longer tail, the shape and size of the sperm head, and membrane composition. The aim of this study was to determine optimal conditions for short-term storage of rat sperm by evaluating their motility and membrane and acrosomal integrity in response to various extender solutions, temperatures, and durations.

The effects of cooling rates and type of freezing extenders on cryosurvival of rat sperm.

Cryopreservation of rat sperm is very challenging due to its sensitivity to various stress factors. The objective of this study was to determine the optimal cooling rate and extender for epididymal sperm of outbred Sprague Dawley (SD) and inbred Fischer 344 (F344) rat strains. The epididymal sperm from 10 to 12 weeks old sexually mature SD and F344 strains were suspended in five different freezing extenders, namely HEPES buffered Tyrode's lactate (TL-HEPES), modified Kreb's Ringer bicarbonate (mKRB), 3% dehydrated skim milk (SM), Salamon's Tris-citrate (TRIS), and tes/tris (TES).

Comparison of cryoprotective effects of iodixanol, trehalose and cysteamine on ram semen.

This study was conducted to improve cryosurvival of electroejaculated (EE) ram semen in the presence of iodixanol (OptiPrep™), trehalose or cysteamine. A tris-based extender was used to prepare 12 extenders containing OptiPrep™ (Op), trehalose (Tr) or cysteamine (Cy) alone, or different combinations of these compounds. Extenders were designated as follows: Tris (control), Op1.