In addition to our services as a toxicology facility, ITR Laboratories Canada has often been asked to perform animal models to meet our clients’ requirements for efficacy or early development. We have subsequently performed ITR-sponsored method development studies which gave acceptable and repeatable results. The designs of those animal model studies are then made available to other clients.
The study of negative and positive effects on wound healing has been performed in rats, rabbits, mini pigs and monkeys. Study designs utilize different methods of wounding depending upon the client’s needs. Incisional wounds are made using a scalpel blade by a trained surgeon. Excisional wounds can also be made by removing a predefined full depth area of skin or a dermatome can be used to remove a specific depth of tissue, such as just the epidermis or deeper into the dermis. Application of a test material can be by injection around the outside of the wound or by topical application into or over the wound.
Wound assessments are made during the in-life phase of the study supplemented by biopsies for histopathological assessment if required and upon completion of the study further histological assessments can be made.
Surgical models are developed by the Veterinary Services group and include removal of specific organs, catheterization and some joint surgeries. Allodynia is a clinical feature of many painful conditions, such as neuropathies. Vet services group at ITR are able to develop a surgical method for an animal model for neuropathies that are characterized by allodynia, the method is using sciatic and facial nerve crushing lesions as well as a surgical technique of implantation of a sciatic nerve cuff in rats and mice. These service are offered on the request of clients as needed.
In collaboration with one of our clients, ITR Laboratories Canada validated an arthritic knee joint pain model in rats. Surgical damage is caused to the cruciate ligament prior to the start of the study. Pain assessments are performed using the paw withdrawal test which utilizes Von Frey filaments and/or a Pressure Application Measurement Device (algometer).
The Von Frey filaments have also been utilized on a method development study to allow an assessment of surgical pain following an incisional wound.
Fibrosis is induced in rats following intratracheal administration of bleomycin. The model typically follows a 21 day time course with extensive clinical pathology, histopathology and immunology endpoints available.
ALI is induced in rats following intratracheal administration of lipopolysaccharide. The model typically follows a 2 day time course with extensive clinical pathology, histopathology and immunology endpoints available.
Hypersensitization is assessed following repeated nose-only inhalation exposure, a latency period then single inhalation challenge exposure. Ovalbumin exposed animals are incorporated as positive controls. Respiratory parameters, Draize scoring, clinical pathology, histology and immunology endpoints are typically assessed to ensure compliance with the FDA guidance “Immunotoxicology Evaluation for Investigational New Drugs” (2002).