Novel Morphological Alteration and Neural Pathway of NADPH Diaphorase Positivity in the Spinal Cord with Disc Herniation of Aged Dog: A Case Report

Abstract

Neuronal lesion or injury is a traditional approach to investigate neural circuit. Is any new neural pathway or new neurodegeneration related central nerve system injury? Spinal disc herniation can cause the spinal cord injury. However, the histological examination is still lack. It happened that a case of spinal disc herniation of a 10-year old dog was examined with NADPH diaphorase (N-d) histology. We did not find the N-d neurodegenerative aberrant in the tissue of the mid-rostral lumber segment besides the metamorphoses by the compression of the disc herniation. However, the severe neuropathological changes majorly occurred in the lumbosacral spinal cord. We found more diverse neurodegenerative alterations: the aging-related N-d body (ANB), megaloneurite and N-d homogeneous formazan globule in the lumbosacral spinal cord. We also found that a new circuit pathway (intermedial collateral pathway) showed by a megaloneurite between the lateral collateral pathway and the medial collateral pathway. The enormous notch caused by spinal disc herniation located at the mid-rostral lumber segments. The aging-related neurodegeneration occurred the specific lumbosacral segments. The homogeneous formazan globule was round or oval homogeneous N-d positivity which distributed in the gray matter and dorsal column. In the medulla oblongata, ANBs were revealed in the gracile nucleus, nucleus reticularis lateralis (ventrolateral spinal trigeminal nucleus) and middle of the spinal trigeminal nucleus.

Spacing spheroids, curl-up and coiled neuritic plexus of the sacral spinal cord of aged dog: Hypothesis based on continued NADPH diaphorase histological observations

“…The vacuolated neurodegeneration in the present was consistent with our previous case report of disc herniation [25]. Megaloneurite, ANB or N-d spheroid are relatively specific neurodegeneration in sacral spinal cord of aged dog.…”

“…Combined with our previous report of disc herniation of aged dog [25] and previous report of megaloneurite [24], aging deterioration of N-d positivity in the sacral spinal cord showed selective destruction of N-d neuronal elements, the pathway of N-d input to the sacral spinal cord and spacing pattern of projecting terminals. The spacing mini spheroids in the laminae I of the dorsal horn was similar to the neuropil spheroids in the neuropathological changes of the frontotemporal dementia [40].…”

A pathway of NADPH diaphorase positivity between central canal and pial surface at anterior fissure in spinal cord: Supra fissure area with hypothesis configuring from dog, rat, monkey and pigeon

“…Next, we examined the same segment of the sacral spinal cord in aged dog. As the previous investigation, the ANBs and megaloneurites were detected in the sacral spinal cord in aged dog [24,29]. The caudal sacral spinal cord occurred relative a smaller number of the megaloneurites than the rostral sacral.…”

“…We also found some positive neurons were detected in the anterior horn [22]. Recently, neuronal circuit of N-d positivity are considered as functional structures in both normal and aging organizations [23][24][25][26]. The present study aimed to specify hypothetic observation: supra fissure area between the central canal and the anterior median fissure the spinal cord.…”