Animal Care Services

All rodent tumor lines and/or non-rodent tumor lines that have been passaged in rodents must be tested and certified free of adventitious rodent pathogens, including those obtained from ATCC.  The assay will be conducted through Animal Care Services (ACS, x22978) for investigators; this permits ACS to maintain a copy of the results for regulatory purposes.  Investigators will provide ACS the recharge account information and assay-ready materials.  ACS will counsel investigators regarding the results obtained.  Periodic testing of the tumor cell lines may be required.

The maximum allowable tumor size is 1.5 cm in mice and 2.5 cm in rats, as determined by measuring the tumor’s largest diameter.  These guidelines apply to implanted tumors, cell lines and tumors arising spontaneously, and/or those arising from the animal’s genetic alteration(s).  Tumors exceeding these sizes may be allowed only after specific review and approval by the Institutional Animal Care and Use Committee (IACUC) for scientific reasons.   

No animal may be implanted with more than one tumor or injected with a neoplastic cell line in more than one location.  Please keep in mind that not all locations on or within the animal can bear the maximum allowable tumor size.  The presence of large tumors in body cavities such as the cranium or thoracic cavity, or behind the eye places greater limitations on the maximum acceptable size of a growth and greatly impedes the normal functions of the animal.  Large tumors in sites such as the thoracic or abdominal cavity may interfere with vital functions such as respiration.   

It is the responsibility of the principal investigator to ensure animals are observed daily, including weekends and holidays, to monitor tumor growth and evaluate overall clinical condition, taking into account weight loss and indications of pain, distress, or abnormal behavior and physiology.  Common signs of pain and distress in rodents include: 1) ruffled or “spikey” fur (mouse looks unkempt); 2) weight loss which may be mild to severe (cachexia), anorexia, dehydration; 3) ocular discharge; 4) lethargy, depression, or reluctance to move; 5) sitting with the back in a hunched position; 6) ataxia (uncoordinated muscle movements), regional or generalized weakness; 7) tremors, which may be intermittent to persistent depending on the condition of the animal; 8) hypothermia; 9) labored respiration; and 10) cyanosis, or a blue tinge to the mucous membranes.  Animals in pain or distress may not interact with their cagemates or may interact with them in a more aggressive manner.  They may also become more aggressive towards human handling.  Animals may squeal when picked up or when an affected area is touched.  Persistent vocalization and crying indicates substantial pain or distress that must be relieved immediately.  Moribund animals that are unable to access food or water, rodents with CNS signs (paralysis, circling), GI signs (rectal prolapse, severe diarrhea), or respiratory signs (coughing, rales, labored breathing) are to be euthanized.

Tumor size measurements may vary depending on the method used (i.e., caliper versus ruler).  To avoid discrepancies and ensure adequate monitoring of tumor size, tumor size should be measured using calipers.  ACS staff will identify any cage found with animals that have tumors approaching the maximum allowable size limit.  Once a cage is identified, the investigator must ensure tumor measurement occurs within 24 hours.  Following this initial measurement, tumor size must be measured with appropriate frequency depending on the growth rate of the tumor.  Thus, fast-growing tumors should be measured daily, while slow-growing tumors may not require daily measurement.  Tumor size, the method and date of measurement, and the initials of the individual making the measurement must be recorded on the cage card to communicate to ACS staff that the investigator and his/her staff are monitoring tumor size.  Although daily tumor measurements may not be required, the investigator must ensure that animals are observed daily.   

Animals must be euthanized before the tumor exceeds the maximum allowable size, becomes ulcerated, or achieves a size so as to interfere with normal activity.  Ulcerations represent nonviable tissue that will not heal, nor can they be surgically repaired.  An ulcerated tumor may have one of two presentations.  The ulceration may appear as an open, moist lesion or as a scab, which is indicative of a break in the underlying epithelium.  Please note that any disruption of the skin, even pinpoint, represents ulceration.  Any animal that is moribund, cachectic, or exhibits any of the criteria for premature termination specified in the approved protocol must be euthanized.  If you have any questions, please consult a ACS veterinarian (x22978). 

For guidelines on growth of ascitic tumors, please refer to the UF IACUC Policy on Use of Animals for Monoclonal Antibody Production, which is available at:  http://www.iacuc.ufl.edu/AnimalUseGuides/UFPolicyAntibodyProduction.doc

The IACUC will allow the growth of multiple tumors only when sufficient scientific justification is provided.  In cases where multiple tumors are permitted, the combined diameters of all tumors may not exceed 1.5 cm in mice and 2.5 cm in rats. 

The IACUC will consider requests to allow tumors to exceed the maximum allowable size if scientific justification is provided.  The following items should be considered in preparing your request:
 
A detailed justification describing why it is necessary to allow tumors to grow beyond the maximum allowable size must be provided.  Specifically, it should be demonstrated that the experimental aims could not be accomplished if animals are euthanized when tumors reach the maximum allowable size.  Any relevant literature citations supporting your request should be provided. 

Identify the specific studies and the expected number of animals to which the exemption will apply.  For example, will this apply to all animals that will develop tumors or will a smaller subset be used?  Attention should be given to planning your experiments such that the smallest number of animals possible will be permitted to develop larger tumors. 

Establish clear alternative endpoints specific to animals with larger tumors.  Although tumors may be permitted to exceed the maximum allowable size, you will be expected to adhere to other criteria for premature termination regardless of tumor size (e.g., skin ulcerations or impairment of mobility).  A maximum tumor size should also be established; for example, you may be able to obtain the desired data if tumor size is limited to 1.75 cm in a mouse model.  Other specific behavioral or physiological signs of pain or distress that will be used as criteria for premature termination of the animals should be provided.  In addition, if tumors are expected to grow rapidly or larger tumors are expected to produce serious health problems, increased monitoring of these animals for signs of pain or distress may be necessary. 

A means of identifying animals involved in these studies should be discussed with the veterinary staff.  One suggestion would be to mark each cage with a colored sticker and a written statement that tumors will be permitted to exceed the maximum allowable size.

References:
United Kingdom Coordinating Committee on Cancer Research (UKCCCR) Guidelines for the Welfare of Animals in Experimental Neoplasia (Second Edition).  British Journal of Cancer, 77(1):1-10, 1998

Wallace, J.  Humane Endpoints and Cancer Research.  ILAR Journal, 41(2):87-93, 2000.