Infection of mouse colonies with Helicobacter spp. has become an increasing concern for the research community. Although Helicobacter infection may cause clinical disease, investigators may be unaware that their laboratory mice are infected because the pathology of Helicobacter species is host-dependent and may not be recognized clinically. The effects of Helicobacter infections are not limited to the gastrointestinal system and can affect reproduction, the development of cancers in gastrointestinal organs and remote organs such as the breast, responses to vaccines, and other areas of research. The data we present in this review show clearly that unintentional Helicobacter infection has the potential to significantly interfere with the reliability of research studies based on murine models. Therefore, frequent screening of rodent research colonies for Helicobacter spp. and the eradication of these pathogens should be key goals of the research community.

Alopecia (hair loss) occurs in some nonhuman primates housed in captivity and is of concern to colony managers and veterinarians. Here we review the characteristics, potential causes, and treatments for this condition. Although we focus on nonhuman primates, relevant research on other mammalian species is discussed also, due to the relative paucity of studies on alopecia in the primate literature. We first discuss the cycle of hair growth and explain how this cycle can be disrupted to produce alopecia. Numerous factors may be related to hair loss and range from naturally occurring processes (for example, seasonality, aging) to various biologic dysfunctions, including vitamin and mineral imbalances, endocrine disorders, immunologic diseases, and genetic mutations. We also address bacterial and fungal infections, infestation by parasites, and atopic dermatitis as possible causes of alopecia. Finally, we examine the role of psychogenic factors, such as stress. Depending on the presumed cause of the hair loss, various treatment strategies can be pursued. Alopecia in nonhuman primates is a multifaceted disorder with many potential sources. For this reason, appropriate testing for various disease conditions should be completed before alopecia is considered to be related to stress.

Murine noroviruses are a recently discovered group of viruses found within mouse research colonies in many animal facilities worldwide. In this study, we used 2 novel mouse norovirus (MNV) wildtype isolates to examine the kinetics of transmission and tissue distribution in breeding units of NOD.CB17-Prkdc^scid/J and backcrossed NOD.CB17-Prkdc^scid/J × NOD/ShiLtJ (N1) mice. Viral shedding in feces and dissemination to tissues of infected offspring mice were monitored by RT-PCR over a 6-wk period postpartum. Histologic sections of tissues from mice exposed to MNV were examined for lesions and their sera monitored for the presence of antibodies to MNV. Viruses shed in feces of parental and offspring mice were compared for sequence homology of the Orf2 gene. Studies showed that the wildtype viruses MNV5 and MNV6 behaved differently in terms of the kinetics of transmission and distribution to tissues of offspring mice. For MNV5, virus transmission from parents to offspring was not seen before 3 wk after birth, and neither isolate was transmitted between cages of infected and control mice. Susceptibility to infection was statistically different between the 2 mouse strains used in the study. Both immunodeficient NOD.CB17-Prkdc^scid/J mice and NOD.CB17-Prkdc^scid/J × NOD/ShiLtJ offspring capable of mounting an immune response shed virus in their feces throughout the 6-wk study period, but no gross or histologic lesions were present in infected tissues. Progeny viruses isolated from the feces of infected offspring showed numerous mutations in the Orf2 gene for MNV5 but not MNV6. These results confirm previous studies demonstrating that the biology of MNV in mice varies substantially with each virus isolate and mouse strain infected.

Intracardiac injection of human tumor cells into anesthetized nude mice is an established model of bone metastasis. However, intracardiac injection of some human tumor cell lines cause acute neurologic signs and high mortality, making some potentially relevant tumor cell lines unusable for investigation. We showed that intracardiac injection of tumor cells can induce a hypercoagulable state leading to platelet consumption and thromboemboli formation and that pretreatment with intravenous injection of low-molecular–weight heparin (LMWH; enoxaparin) blocks this state. In addition, intravenous injection of enoxaparin before intracardiac injection with 2 different small-cell lung carcinoma lines, H1975 and H2126, dramatically decreased mouse mortality while still generating bone metastases. Therefore, reduction of mortality by pretreatment with LMWH increases the types of cells that can be studied in this metastasis model and decreases the number of animals used.

Young rats treated daily with intraperitoneal 4-vinylcyclohexene diepoxide (VCD) undergo selective destruction of primordial follicles, resulting in gradual ovarian failure resembling the menopausal transition in women. To determine whether VCD has similar effects on ovaries of older rats, adult and peripubertal Sprague–Dawley rats were injected intraperitoneally daily for 30 d with vehicle or VCD at 40 or 80 mg/kg. Body weight, food intake, complete blood counts, and markers of liver injury and renal function were measured during VCD treatment. Complete gross necropsy and microscopic observations were performed on day 31, and ovarian follicles were counted. At 80 mg/kg, VCD destroyed primordial and primary follicles to a similar extent in both adult and peripubertal animals, although adult rats likely started with fewer follicles and therefore approached follicle depletion. Treatment with VCD did not affect body weight, but food intake was reduced in both adult and peripubertal rats treated with 80 mg/kg VCD. Adult rats treated with 80 mg/kg VCD had neutrophilia and increased BUN and creatinine; in addition, 4 of these rats were euthanized on days 25 or 26 due to peritonitis. VCD treatment did not increase alanine aminotransferase levels, a marker of liver injury, although the 80-mg/kg dose increased liver weights. In conclusion, VCD effectively destroys small preantral follicles in adult Sprague–Dawley rats, making them a suitable model of the menopausal transition of women. However, because adult rats were more sensitive to the irritant properties of VCD, the use of a lower dose should be considered.

We evaluated the commonly prescribed analgesic buprenorphine in a postoperative pain model in rats, assessing acute postoperative pain relief, rebound hyperalgesia, and the long-term effects of postoperative opioid treatment on subsequent opioid exposure. Rats received surgery (paw incision under isoflurane anesthesia), sham surgery (anesthesia only), or neither and were treated postoperatively with 1 of several doses of subcutaneous buprenorphine. Pain sensitivity to noxious and nonnoxious mechanical stimuli at the site of injury (primary pain) was assessed at 1, 4, 24, and 72 h after surgery. Pain sensitivity at a site distal to the injury (secondary pain) was assessed at 24 and 72 h after surgery. Rats were tested for their sensitivity to the analgesic and locomotor effects of morphine 9 to 10 d after surgery. Buprenorphine at 0.05 mg/kg SC was determined to be the most effective; this dose induced isoalgesia during the acute postoperative period and the longest period of pain relief, and it did not induce long-term changes in opioid sensitivity in 2 functional measures of the opioid system. A lower dose of buprenorphine (0.01 mg/kg SC) did not meet the criterion for isoalgesia, and a higher dose (0.1 mg/kg SC) was less effective in pain relief at later recovery periods and induced a long-lasting opioid tolerance, indicating greater neural adaptations. These results support the use of 0.05 mg/kg SC buprenorphine as the upper dose limit for effective treatment of postoperative pain in rats and suggest that higher doses produce long-term effects on opioid sensitivity.

The purpose of this study was to evaluate the potential efficacy of 3-dimensional time-of-flight magnetic resonance angiography (TOF-MRA) to validate a canine ischemic stroke model. Ischemic stroke was induced through permanent middle cerebral artery occlusion (MCAO) in 5 healthy Beagle dogs. T2-turbo spin echo images and TOF-MRA were obtained with a 1.5-T magnetic resonance system before and 3 and 10 d after MCAO. In 3 dogs, angiograms of the brain obtained at 3 d after MCAO showed complete occlusion of the MCA; in addition, T2 hyperintensities were present unilaterally in the striatocapsular and cerebral cortex lesions. Partial occlusion of the proximal part of the MCA was identified in the 2 remaining dogs, with T2 hyperintensities present only in the striatocapsular lesions. The occluded sites were confirmed at necropsy. The results of this study demonstrate the potential of TOF-MRA to provide a detailed description of intracranial arteries and aid in the evaluation of flow impairment in a canine MCAO model.

The causes and treatments of pancreatitis have been studied in diverse species, but the canine pancreatitis model has been used most often due to its similarities to the condition in humans. Although pancreatitis in dogs can be induced readily by numerous methods, managing these dogs can be difficult because they often develop severe abdominal pain, vomiting, inappetance, and lethargy. In an effort to study pancreatitis, we performed a pilot study to determine whether an endoscopic pancreatic procedure would be possible in a dog and whether, through various manipulations, a new method of inducing pancreatitis could be developed. The model uses endoscopic retrograde cholangiopancreatography (ERCP), a common procedure in human gastroenterology that has been associated with postprocedural pancreatitis. Although all 8 dogs used in developing the ERCP model had both biochemical and histologic changes consistent with pancreatitis, 7 of the 8 dogs remained free of classic clinical signs of the disease. This method is presented as a refinement of a canine model and presents an alternative method of inducing pancreatitis, with decreased risk of developing associated clinical signs.

Herpes simplex virus type 1 (HSV1) is widely used as a gene delivery vector in a variety of laboratory animals. In a recent study, a thymidine-kinase–inactive (replication-conditional) HSV1 used as a delivery vector was lethal in naked mole rats, whereas mice infected with the identical virus showed no adverse effects. This result prompted us to undertake a controlled comparative histologic study of the effect of HSV1 infection on naked mole rats and mice. Replication-competent and replication-conditional HSV1 caused widespread inflammation and necrosis in multiple organ systems of naked mole rats but not mice; naked mole rats infected with replication-defective virus showed no adverse effects. We conclude that the lethality of HSV1 for naked mole rats is likely the result of overwhelming infection, possibly in part due to this species' natural lack of proinflammatory neuropeptides at the initial site of infection.