Abstract4T1 mouse mammary tumor cells can be implanted sub-cutaneously in nu/nu mice to form palpable tumors in 15 to 20 days. This xenograft tumor model system is valuable for the pre-clinical in vivo evaluation of putative antitumor compounds.The 4T1 cell line has been engineered to constitutively express the firefly luciferase gene (luc2). When mice carrying 4T1-luc2 tumors are injected with Luciferin the tumors emit a visual light signal that can be monitored using a sensitive optical imaging system like the IVIS Spectrum. The photon flux from the tumor is proportional to the number of light emitting cells and the signal can be measured to monitor tumor growth and development. IVIS is calibrated to enable absolute quantitation of the bioluminescent signal and longitudinal studies can be performed over many months and over several orders of signal magnitude without compromising the quantitative result.Tumor growth can be monitored for several days by bioluminescence before the tumor size becomes palpable or measurable by traditional physical means. This rapid monitoring can provide insight into early events in tumor development or lead to shorter experimental procedures.Tumor cell death and necrosis due to hypoxia or drug treatment is indicated early by a reduction in the bioluminescent signal. This cell death might not be accompanied by a reduction in tumor size as measured by physical means. The ability to see early events in tumor necrosis has significant impact on the selection and development of therapeutic agents.Quantitative imaging of tumor growth using IVIS provides precise quantitation and accelerates the experimental process to generate results. ProtocolA wide variety of luciferase expressing cancer cell lines can be used for pre-clinical research in mouse models.These cells are provided as a pathogen-free frozen culture, which will readily grow in standard media with no need for selection markers.For our experiment, we'll use the 4T1-luc2 murine mammary tumor cell line, which expresses the luciferase gene that serves as an optical indicator of gene expression or tumorgenesis in vivo. We will use luciferase expression to track growth of the primary tumor non-invasively, but they can also be used to locate and monitor metastatic lesions.Luciferase activity must be verified before injection, and in order to do this, a 90% confluent flask is harvested by trypsinization and then counted. 50,000 cells are then dispensed in a single well of a microtiter plate and serial dilutions are performed. Luciferin is added to the wells at 150ug per ml and incubated for 2 minutes. The microplate can be imaged in IVIS or a luminescent plate reader to determine expression levels. This cell line expresses up to 6500 photons per second per cell, but any expression level above 500 photons per second per cell can be imaged successfully in vivo. Now that we have cells of optimal activity, we can proceed to the subcutaneous injection step.In order to facilitate optimal detection of the tumor, we are using an athymic immuno...

We developed a method for simultaneous in vivo biophotonic monitoring of pneumococcal meningitis and the accompanying neuronal injury in live transgenic mice. Streptococcus pneumoniae engineered for bioluminescence (lux) was used for direct visualization of disease progression and antibiotic treatment in a mouse model of meningitis. The host response was monitored in transgenic mice containing an inducible firefly luciferase (luc) reporter gene under transcriptional control of the mouse glial fibrillary acidic protein (GFAP) promoter. Based on the different spectra of light emission and substrate requirements for lux and luc, we were able to separately monitor the two reporters using a highly sensitive in vivo imaging system. The level of neuronal damage and recovery following antibiotic treatment was dependent on the time of treatment. This model has potential for simultaneous multiparameter monitoring and testing of therapies that target the pathogen or host response to prevent neuronal injury and recovery.

Urinary tract infections (UTIs) are among the most common bacterial infections acquired by humans, particularly in catheterized patients. A major problem with catheterization is the formation of bacterial biofilms on catheter material and the risk of developing persistent UTIs that are difficult to monitor and eradicate. To better understand the course of UTIs and allow more accurate studies of in vivo antibiotic efficacy, we developed a catheter-based biofilm infection model with mice, using bioluminescently engineered bacteria. Two important urinary tract pathogens, Pseudomonas aeruginosa and Proteus mirabilis, were made bioluminescent by stable insertion of a complete lux operon. Segments of catheter material (precolonized or postimplant infected) with either pathogen were placed transurethrally in the lumen of the bladder by using a metal stylet without surgical manipulation. The bioluminescent strains were sufficiently bright to be readily monitored from the outside of infected animals, using a low-light optical imaging system, including the ability to trace the ascending pattern of light-emitting bacteria through ureters to the kidneys. Placement of the catheter in the bladder not only resulted in the development of strong cystitis that persisted significantly longer than in mice challenged with bacterial suspensions alone but also required prolonged antibiotic treatment to reduce the level of infection. Treatment of infected mice for 4 days with ciprofloxacin at 30 mg/kg of body weight twice a day cured cystitis and renal infection in noncatheterized mice. Similarly, ciprofloxacin reduced the bacterial burden to undetectable levels in catheterized mice but did not inhibit rebound of the infection upon cessation of antibiotic therapy. This methodology easily allows spatial information to be monitored sequentially throughout the entire disease process, including ascending UTI, treatment efficacy, and relapse, all without exogenous sampling, which is not possible with conventional methods.Urinary tract infections (UTI) are one of the most common bacterial infections in humans (9, 35). The majority of these infections follow instrumentation of the urinary tract, mainly urinary catheterization, with the development of catheter-associated bacteriuria being directly related to the duration of implant (6,18,37,44). Thus, it is commonplace for the incidence of bacteriuria to be as high as 95% in catheterized patients with implants present for 30 days or more (6, 44). Complications with such infections can lead to fever, cystitis, acute pyelonephritis, bacteremia, and death (44). Catheter-associated urinary tract infections are caused by a variety of uropathogens, including Escherichia coli, Klebsiella, Proteus, Enterococcus, Pseudomonas, Enterobacter, Serratia, and Candida (6,44).Typically, the bacterial biofilm growth on urinary catheter and adjacent mucosa accounts for the pathophysiology of catheter-associated UTI (25,26,31). Diseases involving bacterial biofilms are generally chronic and difficult to treat, be...

Noninvasive real-time in vivo bioluminescent imaging was used to assess the spread of Streptococcus pneumoniae throughout the spinal cord and brain during the acute stages of bacterial meningitis. A mouse model was established by lumbar (LP) or intracisternal (IC) injection of bioluminescent S. pneumoniae into the subarachnoid space. Bacteria replicated initially at the site of inoculation and spread progressively from the spinal cord to the brain or from the brain down to the cervical part of the spinal column and to the lower vertebral levels. After 24 hr, animals showed strong bioluminescent signals throughout the spinal canal, indicating acute meningitis of the intracranial and intraspinal meninges. A decline in bacterial cell viability, as judged by a reduction in the bioluminescent signal, was observed over time in animals treated with ceftriaxone, but not in untreated groups. Mice treated with the antibiotic survived infection, whereas all mice in untreated groups became moribund, first in the IC group then in the LP group. No untreated animal survived beyond 48 hr after induction of infection. Colony counts of infected cerebrospinal fluid (CSF) correlated positively with bioluminescent signals. This methodology is especially appealing because it allows detecting infected mice as early as 3 hr after inoculation, provide temporal, sequential, and spatial distribution of bacteria within the brain and spinal cord throughout the entire disease process and the rapid monitoring of treatment efficacy in a nondestructive manner. Moreover, it avoids the need to sacrifice the animals for CSF sampling and the potential manipulative damage that can occur with other conventional methods.

Following intracardiac delivery of MDA-MB-231-luc-D3H2LN cells to Nu/Nu mice, systemic metastases developed in the injected animals. Bioluminescence imaging using IVIS Spectrum was employed to monitor the distribution and development of the tumor cells following the delivery procedure including DLIT reconstruction to measure the tumor signal and its location.Development of metastatic lesions to the bone tissues triggers osteolytic activity and lesions to tibia and femur were evaluated longitudinally using micro CT. Imaging was performed using a Quantum FX micro CT system with fast imaging and low X-ray dose. The low radiation dose allows multiple imaging sessions to be performed with a cumulative X-ray dosage far below LD50. A mouse imaging shuttle device was used to sequentially image the mice with both IVIS Spectrum and Quantum FX achieving accurate animal positioning in both the bioluminescence and CT images. The optical and CT data sets were co-registered in 3-dimentions using the Living Image 4.1 software. This multi-mode approach allows close monitoring of tumor growth and development simultaneously with osteolytic activity. Video LinkThe video component of this article can be found at https://www.jove.com/video/2775/ ProtocolLongitudinal imaging is used in pre-clinical studies to follow the progress of a disease or measure the effect of a therapeutic. In oncology, optical methods provide rigorous tools to monitor tumor growth and deliver precise quantitation of cell growth or gene expression at each time point in such a study. Anatomical changes can be measured using a high resolution technique like microCT, but for longitudinal imaging a low X-ray dose must be used to avoid biological artifacts. Optical and microCT images can be co-registered to provide a combination of functional and anatomical data ensuring that maximum information is extracted from the animal model. Cell preparation1. Caliper provides a range of luciferase expressing cancer cell lines for pre-clinical research in mouse models. 2. MDA-MB-231-luc-D2H2LN is a human mammary tumor cell line expressing the luciferase gene which can be used as an optical indicator of tumorgenesis in vivo. This cell line is created from a spontaneous lymph node metastasis that originated from a D3H1 mammary fat pad tumor and is known to aggressively form metastases. 3. The cells are provided as a pathogen-free frozen culture which readily grows in standard media with no need for selection markers. 4. To verify Luciferase activity before injection into the animal a 90% confluent flask is harvested by trypsinization. Luciferase activity is measured by dispensing 50,000 cells in a microtiter plate and performing serial dilution. Intracardiac injection of cells in animals1. Before injection, animals are anesthetized using 3% isoflurane. 2. 1-3 million cells are injected in 50ul volume in to the left ventricle. Cell suspension contains 150ug/ml D-Luciferin to validate injection technique. 3. To confirm a correct intracardiac injection mice are imaged in th...