Comparison of Serial Blood Collection by Facial Vein and Retrobulbar Methods in C57BL/6 Mice.

Many biomedical research protocols for mouse models involve serial blood collection and analysis. Two common techniques for serial blood collection in this species are the retrobulbar (RB, also called retroorbital) and facial vein (FV) methods. However, previous studies comparing these methods typically evaluated collection at a maximum of 2 time points. Here we compared hematologic values, adverse clinical effects, and histopathologic lesions in mice bled either once or serially (6 times) by using the FV or RB method. Mice (n = 48) were divided into 4 groups: single FV, single RB, serial FV and serial RB. Mice in the single-collection groups underwent a single blood collection by the indicated method, whereas those in the serial-collection groups were sampled once weekly for 6 consecutive weeks. All animals were euthanized and necropsied 2 wk after their last blood collection. Compared with all other groups, the serial FV group experienced more serious clinical adverse events, including 33% mortality, convulsions, head tilt, and hemorrhage from the ear canal and nares. In addition, mice in the FV groups had a significantly greater acute body weight loss compared with mice in the RB groups. Histologically, mice in both serial-collection groups had an increased incidence of tissue lesions compared with their respective single-collection groups. Importantly, only mice in the serial FV group had life-threatening histopathologic lesions, including cerebral hemorrhage or ischemia. Given these data, we conclude that serial blood collection in mice causes increased incidence of tissue damage compared with single sampling, and serial blood collection by the FV method causes substantial morbidity and mortality compared with the RB method.

Cervical chordoma in a domestic ferret (Mustela putorius furo) with pulmonary metastasis.

A 4-year-old, male neutered domestic ferret (Mustela putorius furo) was evaluated for a mass in the left cervical region. The owner elected humane euthanasia, and an autopsy was performed, revealing a neoplasm with infiltration into the left cranial articular fovea of the atlas and cervical vertebrae, with regional compression of the spinal cord. Histologic evaluation was consistent with cervical chordoma. At autopsy, a left cranial lung lobe nodule was observed. Additional sectioning and histologic evaluation revealed multiple foci of metastatic chordoma at this site. A small focus of micrometastasis was also detected in a section from the right lung lobes. Chordoma is the most common musculoskeletal neoplasm of ferrets, arising from remnant fetal notochord. To our knowledge, pulmonary chordoma metastasis has not been previously reported in the ferret. This case demonstrates the potential for visceral metastasis of chordoma in the ferret, as has been reported in other species.