IN VIVO

Animal models are persuasive tools, both for building pre-clinical proof-of-concepts, and for assessing the efficacy, mechanism of actions and safety profile of lead compounds. At RxCelererate, we offer an extensive range of animal models in diverse disease areas.
Our routine models are industry-standard, accompanied by comprehensive comparator data with approved compounds. We also develop RxCelerate refined models that are fit for purpose and aim to unlock untrodden development opportunities. This innovative approach reflects the individual needs of the client and benefits from additional end-points, delivering more data at no additional cost.

RxCelerate offers the full range of pharmacokinetic protocols in rodents following dosing with test agent via the oral, intravenous or subcutaneous route. Our studies are conducted in accordance with the 3Rs; we use the minimum number of animals possible and routinely test for potential adverse effects to aid with early de-risking of novel compounds.




InVivo mouse image

Induction of allergic asthma and COPD via repeated intra-tracheal OVA (± LPS) in BN rats

Ovalbumin (OVA), derived from chicken egg, is a frequently used allergen that induces robust, allergic pulmonary inflammation in laboratory rodents. When given by intra-tracheal injection, the acute challenge reproduces many of the key features of clinical asthma, including elevated levels of IgE, airway inflammation, goblet cell hyperplasia, epithelial hypertrophy and persistent airway hyper-responsiveness.

RxCelerate have refined the classical model of allergic asthma by controlling the amount of endotoxin delivered via OVA to the lungs of Brown Norway (BN) rats. This means that the inflammatory response can be directed towards either the TH1 or TH2 pathway, giving us the option to investigate both allergic asthma and/or chronic obstructive pulmonary disease (COPD).

Systemic lupus erythematosus mouse strains

Lymphoproliferation mutant mice (MRL/MpJ-Faslpr/J) show systemic autoimmunity, arthritis, immune complex glomerulonephrosis and massive lymphadenopathy associated with proliferation of aberrant T cells, rendering them an appropriate model of systemic lupus erythematosus (SLE).

Mouse strain NZM2410/J are susceptible to developing severe SLE. Animals show accelerated disease onset and develop systemic autoimmunity and glomerulonephritis by 5 months of age.

NZBWF1/J mice have been used as a model of human SLE since the early 1960s. SLE in these mice is characterised by high levels of antinuclear antibodies, haemolytic anaemia, proteinuria and progressive immune complex glomerulonephritis. Females display a higher incidence and increased severity of the disease.

Using these SLE-susceptible mouse strains, we monitor disease progression by the presentation of autoantibodies in the blood, protein in the urine as a marker of nephropathy, and behavioural changes as an indicator of brain damage. Our in vitro team maximises the data generated by selecting the most appropriate ex vivo measurements in blood, cells and tissues.


LPS-induced acute inflammation in female CD1 mice as a model of sepsis

Lipopolysaccharide (LPS)-induced acute inflammation in female CD1 mice replicates the inflammatory dysregulation seen in human sepsis. This endotoxin can be introduced in high dose via the intraperitoneal route and causes a shock-like state in the animal. Determining the cytokine profile in the mice, amongst other biomarkers, indicates the level of inflammation induced by the LPS. This model is equally suitable for use in rats.

There are common experimental biases associated with the use of this model. RxCelerate made some refinements in the amount of LPS dosed to the animals to avoid these biases, which increased end-point validity and data reproducibility between animals.

InVivo Blood Clotting image

Haemophilia A knockout mice

Haemophilia A KO mice (B6;129S-F8tm1Kaz/J) have been genetically engineered to be deficient in clotting factor VIII. Mice are treated with compounds that have the potential to prevent excessive bleeding, and then a tail clip transection is performed. The amount of blood loss at intervals over a 30 minute period is measured using haemoglobin assays.

Previous studies of this nature have transected the tail 2 mm from the tip; a region that will vary in thickness from mouse to mouse. RxCelerate have refined this model by ensuring the tail is always transected at a diameter of 1 mm, irrespective of the distance from the tip.

Sprague Dawley rats

WT rats are treated with anti-coagulants with or without reversal agents, and then a tail clip transection is performed. The amount of blood loss at intervals over a 30 minute period is measured using haemoglobin assays.

Previous studies of this nature have transected the tail 5 mm from the tip; a region that will vary in thickness between rats. RxCelerate have refined this model by ensuring the tail is always transected at a diameter of 3 mm, irrespective of the distance from the tip.

Our bleeding time studies have contained up to 12 experimental groups; an example of our data-rich philosophy.

Thrombosis

Induction of arterial or venous thrombosis in mouse or rats either by ferric chloride (FeCl3) application, or via a laser beam imaged under a intravital microscope (IVM). The efficacies of anti-coagulant agents are tested on the resulting platelet-rich, fibrin poor thrombus.

RxCelerate’s IVM technique is far from routine; the set-up, execution and analysis are highly bespoke, performed by our specialist intravital microscopist.

InVivo Liver image

Nonalcoholic Steatohepatitis in C57BL/6J mice

Nonalcoholic Steatohepatitis (NASH) can be induced in C57 mice via a diet high in fat and fructose. This “fast-food diet” causes mice livers to develop many pathological characteristics of human NASH, including macrovesicular steatosis, acute inflammation, centrilobular fibroplasia and biliary epithelial hyperplasia.

RxCelerate refined and developed a custom high fat and fructose diet, which was easier to handle, more palatable to the animals and produced the pathological hallmarks of NASH within just 12 weeks of starting the diet.

Alpha-1 antitrypsin deficiency and liver disease in the PiZ mouse

These mice have been bred on a C57 background and are transgenic for the Z-mutation of the human A1AT gene, which causes plasma alpha-1 antitrypsin (A1AT) deficiency and liver cirrhosis due to hepatic accumulation of A1AT aggregates. The level of (human) A1AT in the plasma of PiZ mice reflects those seen in Z-mutant humans (~ 10% of WT levels).

Inheritance of the Z-mutant gene in the PiZ mouse population isn’t fully understood. It has been proposed to resemble a Mendelian pattern, although RxCelerate noticed that Z-A1AT protein in the plasma of PiZ mice can vary greatly, even for a given genotype. This could mean that overall levels within a colony could “creep” up, or down, over time. RxCelerate has been managing the PiZ colony via selective breeding, ensuring that Z-A1AT plasma protein remains at a level that appropriately reflects the human condition. Only these mice are selected for studies.

SUGEN + hypoxia in C57BL/6J mice and SD rats

Combining a vascular endothelial growth factor receptor (VEGFR) antagonist, SUGEN 5416 (SU5416), with chronic hypoxia causes pronounced pulmonary arterial hypertension (PAH) in mice and rats. Specifically, the SU5416/hypoxia (SuHx) animals develop increased right ventricular systolic pressure (RVSP), right ventricular hypertrophy (RVH) and angioobliterative lesions in pulmonary arterioles; symptoms which are consistent with human PAH seen in the clinic.

RxCelerate has modified the length of time animals spend in hypoxic conditions, as well as the duration of SU5416 dosing, in order generate a PAH model that most accurately reflects the human condition.

Middle cerebral artery occlusion as a model of stroke in Sprague Dawley rats

Male Sprague Dawley rats are subjected to up to 2 hours of temporary, middle cerebral artery occlusion (MCAO) by intraluminal silicon coated sutures. Neurobehavioural function and cerebral infarction volume are measured to indicate the severity of a stroke-like condition. As this is a reversible technique, sutures can be removed, leading to reperfusion in the affected area and the return of neurobehavioural function, depending on the length of time of the occlusion.

InVivo Metabolic image

The ApoE KO mouse as a model of atherosclerosis

Mutations in ApoE or the receptor for low-density lipoprotein (Ldl) in humans are associated with hyperlipidemic disorders, leading to an increased susceptibility to atherosclerosis. Mice homozygous for the Apoetm1Unc mutation (ApoE KO mice), and mice homozygous for the Ldlrtm1Her mutation (Ldlr KO mice), show an increase in plasma cholesterol levels and develop atherosclerotic plaques to varying extents under specific dietary conditions. Fibrous vascular plaques appear by 20 weeks of age, and feeding a Western diet can accelerate plaque progression. ApoE KO and Ldl KO mice show many similarities to human atherosclerosis; such as the development of vascular fatty streaks, vascular plaques, fragmentation of the elastic lamina, as well as calcification and wall thinning, making both models suitable for human atherosclerosis research.

Models of neuropathic pain

Neuropathic pain in humans usually arises as a consequence of a lesion or a disease affecting the somatosensory system. This can be reproduced in rodents using the well-established techniques of either partial ligation or chronic constriction injury (CCI) of the sciatic nerve, which induce hyperalgesia and allodynia-like symptoms.

At RxCelerate, we are proficient in both partial ligation and CCI. We perform blinded weight-bearing tests to measure hyperalgesia, and use von Frey hairs to measure allodynia.

InVivo Arthritis image

Monosodium Iodoacetate induction of osteoarthritis in Wistar rats

Osteoarthritis (OA) is induced in rats by injecting monosodium iodoacetate (MIA) into the articular space of the hind knee. Hind limb pain is then measured using an incapacitance test meter to determine the level of OA induction. This model is equally suitable for use in mice (endorsed by Simon Westbrook).

RxCelerate refined this model by removing the bias associated with measuring incapacitance by randomising the OA knee and by blinding the operator. In addition, we developed the model to be capable of testing compounds in both a prophylactic and therapeutic paradigm.


Rat medial meniscal tear model of osteoarthritis

Unilateral medial meniscal transection in rats results in rapidly progressive changes in cartilage degeneration, characterised by chondrocyte and proteoglycan loss, fibrillation, osteophyte formation and chondrocyte cloning. These degenerative changes are morphologically similar to those seen in human OA, but occur much more rapidly in rats.


Collagen-induced arthritis in DBA/1J mice as a model of rheumatoid arthritis

Genetically susceptible DBA/1J mice are immunised with a type II bovine collagen emulsion in complete Freund's adjuvant (CFA). Mice typically develop signs of rheumatoid arthritis (RA) disease 26 to 35 days after the initial injection.

Injecting collagen emulsion in CFA causes ulcers around the injection site if the emulsion leaks from the injection wound. RxCelerate have modified this procedure to make the emulsion thicker, preventing leakage and subsequent ulcer formation.

Surgical adhesions

Standard methods in mice that mimic post-surgical adhesions seen in human patients involve peritoneal abrasions and/or the creation of peritoneal buttons.

All too often, quantifiable, reproducible data using these standard approaches is difficult to achieve. RxCelerate have overcome this by securing the two tissues in close proximity with sutures, so that the exact location, number and tenacity of each adhesion can be measured.