Transcortical photothrombotic pyramidotomy model with persistent motor deficits

PLoS One. 2018 Dec 31;13(12):e0204842. doi: 10.1371/journal.pone.0204842. eCollection 2018.

Abstract

Traditional pyramidotomy models have a high mortality rate from breathing difficulties and show early recovery from the induced motor deficits. This study establishes a novel pyramidotomy technique in Sprague Dawley rats that generates persistent motor deficits and has a reduced mortality rate. We used viral neural tracing to identify the course and relative distribution of forelimb and hindlimb motor fibers (n = 9). On basis of the neural tracing data, the medullary pyramid was targeted dorsally from the cerebellar cortex for photothrombotic infarct lesioning (n = 18). The photothrombotic technique selectively destroyed the corticospinal fibers in the medullary pyramid with relative preservation of neighboring grey-matter tissue. MicroPET imaging using 2-deoxy-2-[18F]-fluoro-D-glucose (FDG-microPET) showed a decrease in regional cerebral glucose metabolism (rCGM) in the bilateral pyramid and ipsilateral sensory cortex (p < 0.001, FDR q < 0.05). In addition, the trapezoid bodies and superior olivary nuclei showed a decrease in rCGM, compatible with damage caused during the introduction of the optical fiber. Connected structures such as the inferior colliculi and auditory cortices also showed decreases in rCGM in both hemispheres (p < 0.001, FDR q < 0.05). There was a significant and persistent decrease in motor and sensory function in the contralateral limb following pyramidotomy, as demonstrated by performance in the single pellet reaching task and the foot-fault test. There was no operative mortality or loss of respiratory function in this study. These results indicate that photothrombotic pyramidotomy with a dorsal transcortical approach is a safe and reliable technique for generating a pyramidotomy model with persistent motor deficits.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Auditory Cortex* / diagnostic imaging
  • Auditory Cortex* / physiopathology
  • Disease Models, Animal
  • Fluorodeoxyglucose F18 / pharmacology*
  • Male
  • Motor Cortex* / diagnostic imaging
  • Motor Cortex* / physiopathology
  • Motor Disorders* / diagnostic imaging
  • Motor Disorders* / physiopathology
  • Motor Neurons*
  • Positron-Emission Tomography*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Fluorodeoxyglucose F18

Grants and funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Basic Science Research Program through National Research Foundation of Korea funded by the Ministry of Science and ICT (NRF-2016R1A2B3009660; www.nrf.re.kr) to H-IK, the "Biomedical Integrated Technology Research" Project through a grant provided by Gwangju Institute of Science and Technology (NN16540; www.gist.ac.kr) to H-IK in 2017 and "the Research Institute of Clinical Medicine, Chonnam University Hospital (CRI 13072-3; www.cnuh.com) to M-CL.