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Huber P, Ausk BJ, Tukei KL, Bain SD, Gross TS, Srinivasan S. A convolutional neural network to characterize mouse hindlimb foot strikes during voluntary wheel running. Front Bioeng Biotechnol 2023; 11:1206008. [PMID: 37383524 PMCID: PMC10299834 DOI: 10.3389/fbioe.2023.1206008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/30/2023] [Indexed: 06/30/2023] Open
Abstract
Voluntary wheel running (VWR) is widely used to study how exercise impacts a variety of physiologies and pathologies in rodents. The primary activity readout of VWR is aggregated wheel turns over a given time interval (most often, days). Given the typical running frequency of mice (∼4 Hz) and the intermittency of voluntary running, aggregate wheel turn counts, therefore, provide minimal insight into the heterogeneity of voluntary activity. To overcome this limitation, we developed a six-layer convolutional neural network (CNN) to determine the hindlimb foot strike frequency of mice exposed to VWR. Aged female C57BL/6 mice (22 months, n = 6) were first exposed to wireless angled running wheels for 2 h/d, 5 days/wk for 3 weeks with all VWR activities recorded at 30 frames/s. To validate the CNN, we manually classified foot strikes within 4800 1-s videos (800 randomly chosen for each mouse) and converted those values to frequency. Upon iterative optimization of model architecture and training on a subset of classified videos (4400), the CNN model achieved an overall training set accuracy of 94%. Once trained, the CNN was validated on the remaining 400 videos (accuracy: 81%). We then applied transfer learning to the CNN to predict the foot strike frequency of young adult female C57BL6 mice (4 months, n = 6) whose activity and gait differed from old mice during VWR (accuracy: 68%). In summary, we have developed a novel quantitative tool that non-invasively characterizes VWR activity at a much greater resolution than was previously accessible. This enhanced resolution holds potential to overcome a primary barrier to relating intermittent and heterogeneous VWR activity to induced physiological responses.
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Ochocki DN, Loflin BE, Ahn T, Colglazier KA, Young AR, Snider AA, Bueckers EP, Wojtys EM, Schlecht SH. Endurance running during late murine adolescence results in a stronger anterior cruciate ligament and flatter posterior tibial slopes compared to controls. J Exp Orthop 2022; 9:3. [PMID: 34978644 PMCID: PMC8724477 DOI: 10.1186/s40634-021-00439-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/24/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Anterior cruciate ligament (ACL) injury rates continue to rise among youth involved in recreational and competitive athletics, requiring a better understanding of how the knee structurally and mechanically responds to activity during musculoskeletal growth. Little is understood about how anatomical risk factors for ACL injury (e.g., small ACL size, narrow intercondylar notch, and steep posterior tibial slope) develop and respond to increased physical activity throughout growth. We hypothesized that the ACL-complex of mice engaged in moderate to strenuous physical activity (i.e., endurance running) throughout late adolescence and young adulthood would positively functionally adapt to repetitive load perturbations. METHODS Female C57BL6/J mice (8 weeks of age) were either provided free access to a standard cage wheel with added resistance (n = 18) or normal cage activity (n = 18), for a duration of 4 weeks. Daily distance ran, weekly body and food weights, and pre- and post-study body composition measures were recorded. At study completion, muscle weights, three-dimensional knee morphology, ACL cross-sectional area, and ACL mechanical properties of runners and nonrunners were quantified. Statistical comparisons between runners and nonrunners were assessed using a two-way analysis of variance and a Tukey multiple comparisons test, with body weight included as a covariate. RESULTS Runners had larger quadriceps (p = 0.02) and gastrocnemius (p = 0.05) muscles, but smaller hamstring (p = 0.05) muscles, compared to nonrunners. Though there was no significant difference in ACL size (p = 0.24), it was 13% stronger in runners (p = 0.03). Additionally, both the posterior medial and lateral tibial slopes were 1.2 to 2.2 degrees flatter than those of nonrunners (p < 0.01). CONCLUSIONS Positive functional adaptations of the knee joint to moderate to strenuous exercise in inbred mice offers hope that that some anatomical risk factors for ACL injury may be reduced through habitual physical activity. However, confirmation that a similar response to loading occurs in humans is needed.
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Affiliation(s)
- Danielle N Ochocki
- Department of Orthopaedic Surgery, Indiana University School of Medicine, VanNuys Medical Science Building, Room 0028, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Benjamin E Loflin
- Department of Orthopaedic Surgery, Indiana University School of Medicine, VanNuys Medical Science Building, Room 0028, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Taeyong Ahn
- Department of Orthopaedic Surgery, Indiana University School of Medicine, VanNuys Medical Science Building, Room 0028, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Kaitlyn A Colglazier
- Department of Biomedical Engineering, Indiana University Purdue University-Indianapolis, Indianapolis, IN, USA
| | - Andrew R Young
- Department of General Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anna A Snider
- Department of Orthopaedic Surgery, Indiana University School of Medicine, VanNuys Medical Science Building, Room 0028, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Elizabeth P Bueckers
- Department of Orthopaedic Surgery, Indiana University School of Medicine, VanNuys Medical Science Building, Room 0028, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Edward M Wojtys
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Stephen H Schlecht
- Department of Orthopaedic Surgery, Indiana University School of Medicine, VanNuys Medical Science Building, Room 0028, 635 Barnhill Drive, Indianapolis, IN, 46202, USA. .,Department of Biomedical Engineering, Indiana University Purdue University-Indianapolis, Indianapolis, IN, USA.
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Majerczak J, Filipowska J, Tylko G, Guzik M, Karasinski J, Piechowicz E, Pyza E, Chlopicki S, Zoladz JA. Impact of long-lasting spontaneous physical activity on bone morphogenetic protein 4 in the heart and tibia in murine model of heart failure. Physiol Rep 2020; 8:e14412. [PMID: 32319199 PMCID: PMC7174143 DOI: 10.14814/phy2.14412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 03/04/2020] [Accepted: 03/08/2020] [Indexed: 11/27/2022] Open
Abstract
Bone morphogenetic protein 4 (BMP4) plays an important role in bone remodeling and in heart failure pathogenesis. The aim of this study was to evaluate the effect of spontaneous physical activity on the expression of BMP4 in the heart and tibia of the transgenic (Tgαq*44) mice, representing a model of chronic heart failure. Tgαq*44 and wild-type FVB mice (WT) were randomly assigned either to sedentary or to trained groups undergoing 8 weeks of spontaneous wheel running. The BMP4 protein expression in heart and tibiae was evaluated using Western immunoblotting and the phosphorus and calcium in the tibiae was assessed using the X-ray microanalysis. BMP4 content in the hearts of the Tgαq*44-sedentary mice was by ~490% higher than in the WT-sedentary mice, whereas in tibiae the BMP4 content of the Tgαq*44-sedentary mice was similar to that in the WT-sedentary animals. Tgαq*44 mice revealed by ~28% poorer spontaneous physical activity than the WT mice. No effect of performed physical activity on the BMP4 content in the hearts of either in the Tgαq*44 or WT mice was observed. However, 8-week spontaneous wheel running resulted in a decrease in the BMP4 expression in tibiae (by ~43%) in the group of Tgαq*44 mice only, with no changes in their bone phosphorus and calcium contents. We have concluded that prolonged period of spontaneous physical exercise does not increase the risk of the progression of the BMP4-mediated pathological cardiac hypertrophy and does not affect bone mineral status in the chronic heart failure mice.
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Affiliation(s)
- Joanna Majerczak
- Department of NeurobiologyFaculty of Health SciencesPoznan University of Physical EducationPoznanPoland
| | - Joanna Filipowska
- Department of Translational Research and Cellular TherapeuticsCity of HopeDuarteCAUSA
| | - Grzegorz Tylko
- Department of Cell Biology and ImagingInstitute of Zoology and Biomedical Research of the Jagiellonian UniversityKrakowPoland
| | - Magdalena Guzik
- Department of Muscle PhysiologyFaculty of RehabilitationUniversity School of Physical EducationKrakowPoland
| | - Janusz Karasinski
- Department of Cell Biology and ImagingInstitute of Zoology and Biomedical Research of the Jagiellonian UniversityKrakowPoland
| | - Ewa Piechowicz
- Department of Muscle PhysiologyFaculty of RehabilitationUniversity School of Physical EducationKrakowPoland
| | - Elżbieta Pyza
- Department of Cell Biology and ImagingInstitute of Zoology and Biomedical Research of the Jagiellonian UniversityKrakowPoland
| | - Stefan Chlopicki
- Jagiellonian Centre for Experimental TherapeuticsJagiellonian University Medical CollegeKrakowPoland
- Department of PharmacologyJagiellonian University Medical CollegeKrakowPoland
| | - Jerzy A. Zoladz
- Department of Muscle PhysiologyFaculty of RehabilitationUniversity School of Physical EducationKrakowPoland
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Schlecht SH, Martin CT, Ochocki DN, Nolan BT, Wojtys EM, Ashton-Miller JA. Morphology of Mouse Anterior Cruciate Ligament-Complex Changes Following Exercise During Pubertal Growth. J Orthop Res 2019; 37:1910-1919. [PMID: 31042312 PMCID: PMC6700741 DOI: 10.1002/jor.24328] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 04/08/2019] [Indexed: 02/04/2023]
Abstract
Postnatal development and the physiological loading response of the anterior cruciate ligament (ACL) complex (ACL proper, entheses, and bony morphology) is not well understood. We tested whether the ACL-complex of two inbred mouse strains that collectively encompass the musculoskeletal variation observed in humans would demonstrate significant morphological differences following voluntary cage-wheel running during puberty compared with normal cage activity controls. Female A/J and C57BL/6J (B6) 6-week-old mice were provided unrestricted access to a standard cage-wheel for 4 weeks. A/J-exercise mice showed a 6.3% narrower ACL (p = 0.64), and a 20.1% more stenotic femoral notch (p < 0.01) while B6-exercise mice showed a 12.3% wider ACL (p = 0.10), compared with their respective controls. Additionally, A/J-exercise mice showed a 5.3% less steep posterior medial tibial slope (p = 0.07) and an 8.8% less steep posterior lateral tibial slope (p = 0.07), while B6-exercise mice showed a 9.8% more steep posterior medial tibial slope (p < 0.01) than their respective controls. A/J-exercise mice also showed more reinforcement of the ACL tibial enthesis with a 20.4% larger area (p < 0.01) of calcified fibrocartilage distributed at a 29.2% greater depth (p = 0.02) within the tibial enthesis, compared with their controls. These outcomes suggest exercise during puberty significantly influences ACL-complex morphology and that inherent morphological differences between these mice, as observed in their less active genetically similar control groups, resulted in a divergent phenotypic outcome between mouse strains. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1910-1919, 2019.
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Affiliation(s)
- Stephen H. Schlecht
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Colin T. Martin
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | | | - Bonnie T. Nolan
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan
| | - Edward M. Wojtys
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan
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