Small Animal Services

Use of Xenogen IVIS 200 and Leica MZ-FLIII Imaging Systems

These imaging systems allow investigators to visualize and quantitate in vivo tumor growth and metastasis of xenografts after subcutaneous, orthotopic, or systemic introduction into immuno-competent or immuno-compromised animals. The equipment can also be used study in vivo gene expression and the fate of any luminescent or fluorescent material in vivo and in vitro.

Generation of Xenograft Models

Xenografts models are used by Cancer Center investigators to study the behavior of tumor cells in vivo and the role of specific genes in tumor growth and metastasis. The Facility has modified several established xenograft models for stable expression of luciferases (firefly or renilla) or fluorescent proteins (GFPs, YFPs or RFPs). These models or new ones that can be generated by the Core to meet investigator specifications allow Cancer Center investigators to make use of the Facility’s optical imagining capabilities for quantitative analysis of tumor growth and metastasis.

Drug Target Validation

In providing imagable xenograft models and imaging equipment for in vivo analysis of tumor growth and metastasis, the Core provides Cancer Center investigators with the capacity to analyze the in vivo roles of specific genes in cancer-related processes. To further facilitate such studies, the Core has developed the capability of constructing lentiviral vectors encoding cDNAs and small hairpin RNAs (shRNAs) to alter gene expression in xenograft models.

Drug Testing

Perhaps the most important service offered by the Core is to provide models and instrumentation to test drugs for cancer therapy. In conjunction with Drug Target Validation, this service provides the means by which discoveries made by our basic scientists can be translated into testable clinical trails by our clinicians.

Fee Table*

Services provided by the Core generally require technical assistance from the facility technician/manager. However, the Core does offer a training/certification program to allow users to operate instruments themselves at reduced cost.

*Fees listed are for internal users. A surcharge will be added for external users to cover overhead costs.

Pathology Services:

• Necropsy and tissue collection
• Gross exam with report
• Photodocumentation of lesions
• Training in necropsy technique
• Phenotype screening (complete necropsy and histopathology of mutant mice)
• Investigation of embryonic mortality or embryonic phenotypes
• Assistance with development of animal pathology protocols
• Internal review of animal pathology sections of papers for publication
• Assistance with clinical pathology (bloodwork)
   

Animal Histology Core Services:

• Frozen Sectioning
  • Preparation, freezing, and cutting of standard frozen sections
  • Fixing, staining, and cover-slippin
  • Note: Unsupervised investigator use of cryostat allowed following training
• Tissue Trimming
  • Trimming of submitted fixed tissues to ensure best results
  • Decalcification of bone specimens
• Tissue Embedding
  • Correct orientation of samples in paraffin wax
• Tissue Sectioning
  • Basic microtomy to produce standard 4µm paraffin sections
  • Advanced sectioning (e.g., step sectioning, levels, thick sections, etc.)
  • Unstained sections for your lab to perform immunohistochemistry
• Staining
  • Standard and special staining (Please inquire on available stains)
  • Rapid Hematoxylin and Eosin (H&E) for frozen sections
  • Coverslip slides

The ASCP certified histotechnician is experienced in handling animal tissues and assists researchers by providing histology services, training, and consultation. The APC encourages interactions between its staff and your lab for optimal results on your research project. Turnaround time is usually one week or less depending on the project and curent workload. A drop off bin for samples is placed outside of the Core.

Transgenic Core Facility Services

• Injection of plasmid or bacterial artificial chromosome (BAC) DNA into the pronucleus of single cell embryos.
• Injection of homologously recombined embryonic stem cells into mouse blastocysts for the production of knock-in and knockout mice.
• Laser injection of ES cells into 8-cell embryos for production of knock-in and knockout mice.
• Embryonic stem cell culture services, including electroporation of targeting constructs, colony isolation, expansion, freeze down and preparation of ES cell DNA (currently offered on a limited basis).
• Consultation services for optimizing successful transgene expression and design to facilitate downstream imaging and histology.
• Animal Husbandry Consultations; advising investigators on efficient mating procedures.
• Rederivation of transgenic rodent lines, in particular pathogen compromised transgenic mouse lines imported from other institutions.
• Mouse embryo cryopreservation to preserve valuable transgenic mouse models from catastrophic loss or for use by future investigators.
• Lentivirus Microinjection for delivery of transgenes (in development).

How do I submit samples to the histology laboratory for processing and sectioning?

We have a new submission process, outlined below. This new system is designed to improve workflow, provide you with a detailed receipt for services, and document Core usage.

Before registering a PI name and project in the system, please have the following information ready to enter:

• PI and billing contact information
• Grant Title and NIH grant number (if applicable)
• Billing account number

To submit samples:

1. Go to...
2. Click on "New User Registration." Complete requested information, and "Submit"
3. Go back to ... and login.
4. Click on "Animal Pathology Module" in the far left box.
5. Click on "Add New PI" in the middle box. Complete all requested information and "Submit"
6. After the PI is added, select that name in the middle box.
7. Click "Add New Project" in the far right box. Complete requested information and "Submit"
8. After project is entered, select that project name in the far right box, then click "Request Service"
9. Click on "Animal Histology Core Submission Form." Complete requested information and "Submit"
10. You will receive an email with a link to a copy of your submission form.
11. Print out the form and submit the hard copy with your samples to the histology lab at Stearns 411.

For subsequent submissions, you can select the saved PI and project information and just enter a new submission form. A new form should be submitted every time you make a new request to the Animal Histology Core.

Bring the form and tissues to the laboratory in Ziskind 240. If the laboratory is closed, leave the submission form and tissues in the wall mounted drop off bin in the hall.

Please make sure that all cassettes are labeled using a #2 pencil or a marker specific ally designed for histology to resist the solvents used in processing. If you are unsure if the marker you have can be used for histology, please use a #2 pencil or your labels could be lost. Do NOT use Sharpie markers or other lab markers that are not completely solvent resistant. The AHC is not responsible for labels lost in processing due to use of a marker that is not solvent resistant

What is the expected turnaround time for getting slides back?

All work requests are processed in the order in which they are received. Priority is given to Tufts and Tufts Medical Center investigators. Urgent needs may be given priority after approval by the APC Director with additional fees for expedited service. Depending on the project and current lab workload, turnaround time is usually a week or less. If you are planning a large or time-critical project, please contact the laboratory well in advance so that we can plan to accommodate your needs.

Investigators will be notified when their work request is completed and should pick up slides, blocks, remaining tissues, empty containers, etc, as soon as possible. Because the lab does not have storage space, any unclaimed materials may be discarded 90 days after project completion.

I need to use a cryostat for my research project. Can I get training on making frozen sections?

The AHC can provide frozen sections, or investigative staff can use the AHC cryostat on an hourly basis. For an investigator who has not made frozen sections before, we provide detailed training and practice. The histotechnician will be available as you begin to cut sections in case you have additional questions. Supplies can be purchased from the lab, or you can bring your own. Investigators with prior experience using a cryostat will have a brief orientation session on use of the particular model we have in the lab. All investigators using the cryostat must first attend training sessions and demonstrate a sufficient knowledge of the use of the cryostat in order to be approved for unsupervised use of the equipment. AHC staff reserve the right to revoke use of any equipment where it is determined that the user is not sufficiently knowledgeable about its use or is negligent in its use.

I collected different organs in formalin for my research project. Is there anything else I have to do before I submit them to the AHC?

Some small organs (such as mouse adrenal glands or lymph nodes) don’t have to be trimmed, but larger organs must be trimmed to have a flat surface and proper orientation before they are processed. Improper orientation can ruin slides! The AHC offers a service to trim the tissues, or we can train you in trimming techniques. This is a very important step in optimizing the final result (your slide quality), especially with organs such as kidney, brain, heart, liver, and skin. If you cut a tissue, the area you want to look at on the slide should be oriented face down in the cassette. If you have any questions about this important step, please contact the histotechnician or pathologist.

Do I need to do anything special if I am submitting bone?

Yes! Bone should be decalcified to remove the mineral and allow sectioning with the microtome blade. Identify any tissues or cassettes with bone to the histotechnician, and these tissues will be decalcified prior to processing (or you can purchase decalcification solution to use in your laboratory). If you decalcify bones yourself, be careful to only leave them in the solution for only as long as needed to make the bones soft and rubbery. The acid in the solution can ruin tissue morphology if the tissues are left in the solution too long.

Does the core offer IHC (Immunohistochemistry) staining?

The AHC does not currently offer IHC staining but is planning to in the future.   We can still help prepare unstained slides that are ready for IHC staining. Please call the core for additional information.

I would like the pathologist to look at my slides when they are ready. When should I talk to them about the project?

Ideally, talk to the pathologist as early as possible during the planning period. Before you do necropsies and collect the tissues, get the pathologist’s recommendations on which tissues to collect, how to collect them, suggested fixatives, and tissue trimming and orientation. For example, in any studies involving tumors, always take “normal” tissue around the tumor when you collect the tumor, so orientation can be determined, nearby structures such as blood vessels and lymphatics can be studied, and invasiveness can be examined. If you just take the tumor and cut off the adjacent tissue, a lot of valuable information could be lost.

If you have already collected the tissues, contact the pathologist before the slides are made, so that recommendations on trimming and orientation can be made. A quick discussion with the pathologist may save you a lot of money if a few tips on trimming and cassetting the tissues results in fewer slides

Before meeting with the pathologist, complete the pathology request form online, which will provide information on your project objectives and project design.

I am interested in phenotyping a new genetically engineered mouse line that I have developed. How can the pathology service help?

The Animal Pathology Core can provide comprehensive or limited phenotyping services for investigators with genetically engineered mice. This service requires advance discussion and planning with the pathologist. Services include (but are not limited to), organ and body weights, gross examinations, histologic examination of tissues, hematology, and clinical chemistry. Age and sex-matched wild type animals should be submitted at the same time to use as controls for comparison.

How can I get hematology and clinical chemistry tests done on some of my mice?

Although the Animal Pathology Core does not have the equipment to run clinical pathology tests, we can send your samples to IDEXX, a reference laboratory in North Grafton that has the proper equipment and quality control to handle small volumes of rodent blood samples, or to AniLytics, a reference lab in Maryland that specializes in customized tests used in biomedical research. Consult with the APC pathologist regarding the tests you are requesting for information on proper sample collection and handling. The APC pathologist is also available for assistance with interpretation of the results. The veterinary pathology technician can provide training in blood collection techniques or can collect the blood for you. To submit a clinical pathology sample, please contact Lauren Richey.

Small Animal Imaging Core
Call 617.636.6748 or email gary.sahagian@tufts.edu.

Animal Pathology Core

For histology services:
Nathan Li, HT(ASCP), Histotechnician
nathan.li@tufts.edu
617.636.5664

For tissue collection and necropsy services: 


Brian Lagace, RLAT, Veterinary Pathology Technician
brian.lagace@tufts.edu
617.636.2944

For consultation and pathology services:
Lauren Richey, DVM, PhD, Diplomate ACVP, Veterinary Pathologist, Director, Animal Pathology Core
lauren.richey@tufts.edu
617.636.6488
Lab hours: 8:30 a.m. to 3:30 p.m.