Assessment of gait in mice using simplified analysis tools

Gait analysis has received significant attention in many clinical conditions including chemotherapy-induced alterations, degenerative diseases, and hemophilia. Gait changes can be a consequence of physical and/or neural/motor alterations and/or pain. It can provide measurable objective outcomes for following disease progression and the effectiveness of therapy without patient or observer bias. Many devices are available for analyzing gait in clinic. Gait analysis in laboratory mice is frequently used to examine the mechanisms and effectiveness of interventions for movement and pain assessment. However, gait analysis in mice is challenging due to the complexity of image acquisition and analysis of large data sets. We have developed a relatively simple method to analyze gait and validated it using the arthropathy model in hemophilia A mice. We describe artificial intelligence-assisted detection of gait and validation with weight-bearing incapacitance for stance stability in mice. These approaches enable the non-invasive, non-evoked evaluation of pain and the consequent impact of motor function on gait.

NCMP-18. NEUROLOGICAL SEQUELAE IN THE ID8 OVARIAN CANCER MOUSE MODEL: P38/JNK MAPK INHIBITION AS A POTENTIAL THERAPEUTIC FOR CANCER-RELATED COGNITIVE IMPAIRMENTS AND CHEMOTHERAPY-INDUCED PERIPHERAL NEUROPATHY

OBJECTIVES

Chemotherapy-related cognitive impairment (CRCI) and chemotherapy-induced peripheral neuropathy (CIPN) are neurological sequelae of platinum-based chemotherapy. To examine the contribution of cancer itself and additional neurological impairment with chemotherapy, we used the ID8 syngeneic ovarian cancer mouse model and assessed cognition and hyperalgesia +/- cisplatin treatment. We examined the effect of p38 and c-JUN N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) inhibition on cisplatin-induced neuronal damage.

METHODS

B6 female mice were injected with 107 ID8 cells or 0.9% saline, i.p. Mice received cisplatin (2.3 m¬¬¬g/kg/day, i.p.) or 0.9% saline (OvT+CIS, OvT+VEH, respectively) for 5d, followed by 5d of rest for two cycles. Cognition was assessed longitudinally at 69d by the open field test (OFT), novel object recognition (NOR) at 75d and 104d, and novel place recognition (NPR) at 106d post-ID8 implantation. Hyperalgesia was assessed at 113d. Primary mouse and rat hippocampal neurons were pre-treated with VX-745 or SP600125, followed by cisplatin, and neuronal morphology was assessed.

RESULTS

OvT+VEH mice had detectable abdominal tumors 90d post-implantation. At 75d, OvT+VEH and OvT+CIS had impairments in NOR, with discrimination ratios (DR)= 0.52, 0.51, respectively. OvT+VEH showed trending differences vs. OvT+CIS (DR=0.39, DR=0.62, p=0.079) on NOR on 104d, and impairments on NPR on 106d (DR=0.41, DR=0.63, p=0.03). Cisplatin decreased mechanical (p< 0.05) and cold hyperalgesia (p< 0.07, n.s.) in OvT+CIS vs. OvT+VEH. VX-745 and SP600125 pre-treatment in mouse and rat hippocampal neurons prevented cisplatin-induced dendritic branching and spine density loss (p< 0.05).

DISCUSSION

While cisplatin transiently increased anxiogenic behavior, cognitive impairments, and hyperalgesia in OvT+CIS, these deficits persisted longitudinally in OvT+VEH, suggesting ovarian cancer may evoke sensory and progressive neurocognitive deficits in the absence of chemotherapy. Future studies will address hyperalgesia and cognitive differences between healthy control and ovarian cancer mice +/- cisplatin, and whether VX-745 and SP600125 administration ameliorates CRCI/CIPN in this model.

NCMP-13. ID8 OVARIAN CANCER MOUSE MODEL MIMICS NEUROLOGICAL SEQUELAE OF OVARIAN CANCER IN WOMEN

OBJECTIVES

Chemotherapy-related cognitive impairment (CRCI) and chemotherapy-induced peripheral neuropathy (CIPN) are neurological complications of cancer treatment. Cisplatin is used to treat ovarian malignancies, and over 70% of women experience CRCI/CIPN during and after platinum-based chemoTx. However, over 30% of non-CNS cancer patients experience cognitive impairment prior to chemoTx. To examine the contribution of cancer itself and additional neurological impairment with chemoTx, we used an ID8 syngeneic mouse model of ovarian cancer and assessed hyperalgesia and cognition +/- cisplatin treatment.

METHODS

C57BL/6 female mice were injected intraperitoneally with 107 ID8 ovarian cancer cells or 0.9% saline. After 10d of ID8 injections, mice received cisplatin (2.3 mg/kg/day, i.p.) or 0.9% saline (OvT+CIS, OvT+VEH, respectively) for 5d, followed by 5d of rest for 2 cycles. Mechanical and cold hyperalgesia were assessed longitudinally. Cognition was assessed 28d post-chemoTx by the open field test (OFT), novel object recognition (NOR), and novel place recognition (NPR) tasks.

RESULTS

OvT+VEH and OvT+CIS mice developed an increased sensitivity to mechanical ( >200%, p< 0.001) and thermal (cold) stimuli ( >78%, p< 0.004) starting 14d post-ID8 implantation, vs non-tumor controls (CON). In the OFT, OvT+CIS mice had increased anxiogenic behavior (55%, p< 0.001) vs CON, and (46%, p< 0.05) vs OvT+VEH. In NPR, OvT+CIS had reduced discrimination (37%, p< 0.05) vs CON. OvT+VEH and OvT+CIS showed impaired discrimination (25%, p< 0.05 & 33%, p< 0.01, respectively) in NOR vs CON, with trending differences between OvT+CIS vs OvT+VEH in hyperalgesia and cognitive tasks. DISCUSSION: This is the first rodent model to demonstrate that ovarian cancer may evoke sensory and neurocognitive changes in the absence of chemotherapy. Future development of the model will address hyperalgesia and cognitive differences between OvT+VEH vs OvT+CIS. This model has potential for translational studies on the treatment of neurological sequelae of cancer and cisplatin-induced CRCI and CIPN.

Lipid talk: Endocannabinoids regulate mucosal inflammation following helminth infection

More than 2 billion humans carry infectious parasites leading to chronic co-morbidities and growth retardation in children. Parasitic infections induce a T helper type 2 (Th2) immune response in the host to promote clearance which can lead to fibrosis if chronic. We recently showed that infection with the soil-transmitted nematode Nippostrongylus brasiliensis (Nb) induces overproduction of endocannabinoids (eCBs) in the host. Endocannabinoids are endogenous cannabis-like molecules that influence the development of obesity and are anti-inflammatory, however their function in infection is largely unknown. The overproduction of eCBs in Nb-infected mice was observed throughout infection in the infected lung and intestine. Pharmacological inhibition of cannabinoid receptor subtype 1 (CB-1R) with AM6545 (10 mg/Kg/2mL), a peripherally-restricted CB1R neutral antagonist, throughout Nb infection exacerbated weight loss of mice without altering food or water intake. This inhibition of CB1Rs led to a prolonged presence of eosinophils and neutrophils in the broncho-alveolar fluid and an accumulation of lymphocytes in the spleen. Furthermore, CB1R inhibition caused an increase in the expression of the mannose receptor on alveolar macrophages at day 8 post infection, indicating a sustained need for inflammatory resolution. Strikingly, we also found that Nb produces its own eCBs which vary in concentration based on stage of development, and that the eCB system is present in many parasitic nematodes including those that infect humans. These findings suggest that the eCB system is active in several hookworm species, and that host and helminth eCBs may influence immune and anti-inflammatory functions.

Circulating levels of endocannabinoids respond acutely to voluntary exercise, are altered in mice selectively bred for high voluntary wheel running, and differ between the sexes

The endocannabinoid system serves many physiological roles, including in the regulation of energy balance, food reward, and voluntary locomotion. Signaling at the cannabinoid type 1 receptor has been specifically implicated in motivation for rodent voluntary exercise on wheels. We studied four replicate lines of high runner (HR) mice that have been selectively bred for 81 generations based on average number of wheel revolutions on days five and six of a six-day period of wheel access. Four additional replicate lines are bred without regard to wheel running, and serve as controls (C) for random genetic effects that may cause divergence among lines. On average, mice from HR lines voluntarily run on wheels three times more than C mice on a daily basis. We tested the general hypothesis that circulating levels of endocannabinoids (i.e., 2-arachidonoylglycerol [2-AG] and anandamide [AEA]) differ between HR and C mice in a sex-specific manner. Fifty male and 50 female mice were allowed access to wheels for six days, while another 50 males and 50 females were kept without access to wheels (half HR, half C for all groups). Blood was collected by cardiac puncture during the time of peak running on the sixth night of wheel access or no wheel access, and later analyzed for 2-AG and AEA content by ultra-performance liquid chromatography coupled to tandem mass spectrometry. We observed a significant three-way interaction among sex, linetype, and wheel access for 2-AG concentrations, with females generally having lower levels than males and wheel access lowering 2-AG levels in some but not all subgroups. The number of wheel revolutions in the minutes or hours immediately prior to sampling did not quantitatively predict plasma 2-AG levels within groups. We also observed a trend for a linetype-by-wheel access interaction for AEA levels, with wheel access lowering plasma concentrations of AEA in HR mice, while raising them in C mice. In addition, females tended to have higher AEA concentrations than males. For mice housed with wheels, the amount of running during the 30min before sampling was a significant positive predictor of plasma AEA within groups, and HR mice had significantly lower levels of AEA than C mice. Our results suggest that voluntary exercise alters circulating levels of endocannabinoids, and further demonstrate that selective breeding for voluntary exercise is associated with evolutionary changes in the endocannabinoid system.