carbocyanines and Radiculopathy

Pain in lumbar radiculopathy shows a segmental distribution in muscles and bones, requiring knowledge of myotomes and sclerotomes for diagnosis of the involved nerve roots. The rostrocaudal coordinate in sensory space was examined for 49 reference sites placed on the periostium in the spine and hindlimb bones of rats to clarify the sclerotomes. Neurotracer 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was applied to reference sites. DiI-labeled neurons were counted from the T9 through S3 dorsal root ganglia. The coordinate was calculated for each reference site as the location of the "median" neuron of all DiI-labeled neurons. The coordinate was between T13 and L3 for the lumbar spine, L2 and S1 in the coxal bone, L3 and L4 in the hip joint, femur, knee joint, tibia, and first digit, and L5 in the fibula and fifth digit. The routes of sclerotome boundary lines (SBLs) were determined based on the coordinates of the reference sites. SBLs obliquely demarcated the lumbar spine. SBLs were aligned parallel rostrodorsally to caudoventrally in the coxal bone, with medially-oriented convergence. The SBL between L3 and L4, which corresponded to the level of the furcal nerve, passed from the femur, tibia, and toward the first digit in the hindlimb bones.. The present study is the first report of the detailed sclerotome chart of rats. The sclerotome chart is not only useful for basic research of lumbar radiculopathy using rats, but would also facilitate an understanding of the spatial distribution of pain in patients with lumbar radiculopathy.

Topics: Animals; Carbocyanines; Fluorescent Dyes; Hindlimb; Male; Neuroanatomical Tract-Tracing Techniques; Pelvis; Radiculopathy; Rats; Rats, Sprague-Dawley; Sensory Receptor Cells; Spine; Spondylosis

DNA array analysis of dorsal root ganglion (DRG) using a rat model with nerve root constriction.. To determine the molecular changes in the DRG adjacent to the injured nerve root in a lumbar radiculopathy model.. DNA array analysis in lumbar radiculopathy model has so far focused on the spinal dorsal horn. The molecular changes in the DRG adjacent to the injured nerve root in lumbar radiculopathy remain to be determined.. Bilateral L5 DRGs were removed from 12 Sprague-Dawley rats on days 2, 7, 14, and 21 after nerve root ligation and on day 7 from 3 rats with sham operation. The aRNAs from the DRGs with nerve root ligation were labeled with Cy5 dye and those from the opposite side DRG (control) were labeled with Cy3 dye, and then hybridized to a 7793-spot Panorama Micro Array. It was considered to be significantly upregulated, when an average expression ratio of Cy5 to Cy3 was 2 or more. Genes upregulated were classified into early phase group (upregulated on day 2), midphase group (upregulated on days 7 and 14), and continuous group (upregulated from day 2 to 21). Seventeen genes were subjected to validation analysis with real-time quantitative PCR.. There were 16 upregulated genes in the early phase group, 56 genes in the midphase group, and 17 genes in the continuous group. Functional categorization revealed dominantly upregulated gene categories in each group; transcription/translation in the early phase group, enzyme/metabolism in the midphase group, and structure in the continuous group. Validation analysis of 17 genes demonstrated mean relative expression of 2.0 or more in all but 1 gene in the DRGs with nerve root ligation and none of them in the DRGs with sham operation.. The genes identified in this study, especially those involved in pain signaling and inflammation, serve as potential targets for molecular-based therapy for lumbar radiculopathy.

Topics: Animals; Carbocyanines; Disease Models, Animal; Fluorescent Dyes; Ganglia, Spinal; Gene Expression; Gene Expression Profiling; Lumbar Vertebrae; Male; Oligonucleotide Array Sequence Analysis; Pain; Radiculopathy; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Spinal Nerve Roots; Time Factors; Up-Regulation