ABSTRACT
Objective To explore a new efficient extraction method of dorsal root ganglions(DRGs)of rats by exploring and extracting DRGs reversely along the nerve traveling pathway. Methods The DRGs were extracted by the traditional method of opening the intervertebral foramina and the new method, extracting DRGs reversely along the nerve traveling pathway,respectively. The time consuming and the number of intact DRGs obtained with these two method were compared. Results The number of intact DRGs(L3-5segments,both sides)extracted from each rat with the traditional method was(3.08 ± 1.31),and the average time consuming of each DRG was(5.58 ± 1.21)min. As for the new method ,the number of intact DRGs extracted from each rat was(4.29 ± 1.08), and the average time consuming was(1.69 ± 0.91)min,significantly better than that of the traditional method(P < 0.05 for both). Conclusions The new method of exploring and extracting DRGs reversely along the nerve traveling pathway is more efficient for obtaining intact DRGs of rats,providing more useful tissue materials for subsequent culture and morphological studies of DRG cells.
ABSTRACT
BACKGROUND: Compound betamethasone injection has been widely used to treat intervertebral disc herniation, but its precise mechanism remains unclear. OBJECTIVE: To explore effects of local injection of compound betamethasone on substance P and calcitonin gene-related peptide in spinal cord and dorsal root ganglia of rat models undergoing autologous transplantation of nucleus pulposus. METHODS: A total of 36 Sprague-Dawley rats were randomly assigned to four groups: blank group, model group, sham surgery group, and western medicine group, with 9 rats in each group. After 1 week of adaptive feeding, rat models of autologous transplantation of nucleus pulposus were established in the model and western medicine groups. At 3, 7 and 12 days after surgery, the rats were given 128.25 μL saline in the model and sham surgery groups. The rats in the western medicine group were administered Betamethason Compound Injection 13.5 μL + 2% Lidocaine Injection 67.5 μL. At 12 hours after final administration, L4-6 segments of the spinal cord and dorsal root ganglion were obtained, and substance P and calcitonin gene-related peptide contents in L4-6 segments of the spinal cord and dorsal root ganglion were determined using immunofluorescence staining. RESULTS AND CONCLUSION: Significant differences in mean fluorescence intensity of substance P and calcitonin gene-related peptide were detected in rat spinal cord and dorsal root ganglion in each group (P < 0.01). Further paired comparison showed that compared with the blank and sham surgery groups, substance P and calcitonin gene-related peptide contents were significantly higher in the spinal cord and dorsal root ganglion in the model group (P < 0.01), which verified that models could be replicated and were reliable. Compared with the model and sham surgery groups, substance P and calcitonin gene-related peptide contents were significantly lower in the spinal cord and dorsal root ganglion of rats in the western medicine group (P < 0.01). Above results confirmed that Compound Betamethasone Injection for treating lumbar intervertebral disc herniation eliminated substance P and calcitonin gene-related peptide in dorsal root ganglion possibly by inhibiting dorsal root ganglion neuron synthesis and secreting substance P and reduced their transmission to the spinal cord, resulting in inhibiting and lessening pain.