ABSTRACT
PURPOSE: To determine the relationship between change in the expression of the p75 neurotrophin receptor (NTR) and transient receptor potential vanilloid 1 (TRPV1) after a spinal nerve injury with time. MATERIALS AND METHODS: The L5 and L6 spinal nerve of the rats were cut unilaterally. The spinal cord and dorsal root ganglion (DRG) were subjected to immunohistochemistry for p75 NTR and TRPV1. RESULTS: The immunoreaction (IR) for p75 NTR in the neuronal cytoplasm was persistently lower on the ipsilateral L5 and L6 DRG but higher in the satellite cells and fibers. The colocalization between p75 NTR and TRPV1 was increased temporarily in the L4 DRG in both sides. In the spinal cord, p75 NTR-IR decreased temporalily in the ipsilateral dorsal horn of the L4-L6 level and had recovered at 28 days after injury. CONCLUSION: These results show that a differential change in the expression of p75 NTR and TRPV1 is related to the different functional recovery of the sensory and motor system, and that increased colocalizations between p75 NTR and TRPV1 in a non-injured DRG might be related to the development of neuropathic pain after a peripheral nerve injury.
Subject(s)
Animals , Rats , Cytoplasm , Diagnosis-Related Groups , Ganglia, Spinal , Horns , Immunohistochemistry , Neuralgia , Neurons , Peripheral Nerve Injuries , Receptor, Nerve Growth Factor , Spinal Cord , Spinal Nerve Roots , Spinal NervesABSTRACT
PURPOSE: The authors studied the effect of the 3-AB, an inhibitor of poly(ADP-ribose)polymerase (PARP), on the changes of primary afferents and spinal cord after spinal nerve injury. METHOD: The L5 and L6 spinal nerve of the rats were cut, and 3-AB (10 mg/Kg) was injected intraperitoneally once per day. The animals were sacrificed 3 days, 7 days, 14 days and 28 days after nerve injury. Binding of isolectin B4 (IB4) and immunohistochemistry (IHC) of CGRP for the changes in primary afferents, IHC of NK1 for sensory neurons, and of cleaved caspase 3 and NeuN for the apoptotic changes in spinal neurons were performed. RESULT: Decreased binding of IB4 and immunoreactivity (IR) for CGRP, increase of IR for NK1, and cleaved caspase 3 in both neurons and glia in ipsilateral dorsal horn were observed after spinal nerve injury. These changes were attenuated, especially at between 3 days and 14 days, by administration of 3-AB. CONCLUSION: It is suggested that inhibition of PARP by 3-AB may attenuate alterations of primary afferents and spinal neurons, at least in early stage, after spinal nerve injury.
Subject(s)
Animals , Rats , Apoptosis , Caspase 3 , Horns , Immunohistochemistry , Lectins , Neuroglia , Neurons , Sensory Receptor Cells , Spinal Cord , Spinal NervesABSTRACT
PURPOSE: The authors studied the effect of the 3-AB, an inhibitor of poly(ADP-ribose)polymerase (PARP), on the changes of primary afferents and spinal cord after spinal nerve injury. METHOD: The L5 and L6 spinal nerve of the rats were cut, and 3-AB (10 mg/Kg) was injected intraperitoneally once per day. The animals were sacrificed 3 days, 7 days, 14 days and 28 days after nerve injury. Binding of isolectin B4 (IB4) and immunohistochemistry (IHC) of CGRP for the changes in primary afferents, IHC of NK1 for sensory neurons, and of cleaved caspase 3 and NeuN for the apoptotic changes in spinal neurons were performed. RESULT: Decreased binding of IB4 and immunoreactivity (IR) for CGRP, increase of IR for NK1, and cleaved caspase 3 in both neurons and glia in ipsilateral dorsal horn were observed after spinal nerve injury. These changes were attenuated, especially at between 3 days and 14 days, by administration of 3-AB. CONCLUSION: It is suggested that inhibition of PARP by 3-AB may attenuate alterations of primary afferents and spinal neurons, at least in early stage, after spinal nerve injury.
Subject(s)
Animals , Rats , Apoptosis , Caspase 3 , Horns , Immunohistochemistry , Lectins , Neuroglia , Neurons , Sensory Receptor Cells , Spinal Cord , Spinal NervesABSTRACT
Primary afferents sensitive to capsaicin and noxious heat express vanilloid receptor 1(VR1) in both their peripheral and central fibers and terminals. We used multiple immunofluorescence and confocal microscopy to characterize their pattern of termination in rat spinal cord, colocalization of neurochemical markers of primary afferents and other presynaptic receptors. VR1-positive unmyelinated fibers mainly terminate in lamina I, where they co-stain for CGRP, and to a limited extent for SP, and in lamina II, especially its medial half, where they co-stain for IB4. VR1 positive thin myelinated fibers terminate in lamina I and co-stain for the neurochemical tracer CTB, injected in the sciatic nerve. As revealed by simultaneous staining for the synaptic marker synaptophysin, VR1-positive terminals are abundant in lamina I and sparse in lamina II. In L6-S1 spinal cord, VR1-positive fibers and terminals were abundant in Lissauer's tract, lamina I-V, medial collateral path to lamina X, and lateral collateral path to sacral parasympathetic nucleus. Most of VR1 positive fibers in Lissuer's tract and LCP are colocalized with SP. In conclusion, it is suggested that VR1 positive fibers in spinal cord are both peptidergic and non-peptidergic, IB4 positive fibers, mediating both somatic and visceral sensations, and that peptidergic VR1 positive fibers are mainly related with visceral sense.