BACKGROUND: miRNA plays a critical regulatory role in the development and plasticity of spinal cord, and pathological changes after spinal cord injury. OBJECTIVE: To study the effect of miR-136-5p on the A20 expression in mouse astrocytes stimulated by interleukin-17 (IL-17). METHODS: C57BL/6 mouse astrocytes were cultured in vitro, identified by immunofluorescence staining, and then stimulated by 100 μg/L IL-17 for 0, 3, 6, 12 and 24 hours, respectively. The relative mRNA expression levels of IL-6 and tumor necrosis factor-α were detected by RT-PCR to determine the optimal stimulation time of IL-17. The mouse astrocytes were respectively stimulated by 10, 20, 50, 100 and 200 μg/L IL-7 for 6 hours, and similarly, the relative mRNA expression levels of IL-6 and tumor necrosis factor-α were detected to determine the optimal concentration of IL-17. At 6 hours after IL-17 (50 μg/L) stimulation, the mRNA expression levels of miR-136-5p and A20 in mouse astrocytes were detected by RT- PCR, and the protein expression level of A20 was detected by western blot assay. In addition, the lentiviral expression vector (miR-136-5p-inhibition) was constructed and transfected into the mouse astrocytes that were also stimulated by IL-7 to detect the expression levels of miR-136-5p, A20 mRNA and A20 protein. RESULTS AND CONCLUSION: Compared with the blank control group, the expression level of miR-136-5p in the miR-136-5p-inhibition group was significantly decreased after 6-hour IL-17 stimulation (P < 0.05). The expression levels of A20 mRNA and protein in each group were significantly decreased after 6-hour IL-17 (50 μg/L) stimulation (P < 0.05). The expression levels of A20 mRNA and protein in the miR-136-5p-inhibition group were significantly higher than those in the blank control group (P < 0.05), while there were no significant differences in the expression level of A20 protein between blank control and negative groups (P > 0.05). To conclude, miR-136-5p makes certain effect on the expression of A20 protein in astrocytes after IL-17 stimulation.

BACKGROUND: miRNA-136-5 p plays a crucial regulatory role in pathological changes, inflammatory response and regeneration after spinal cord injury. OBJECTIVE: To investigate the effect of miRNA-136-5 p on the expression of cytokines in serum and NF-κB protein in spinal cord in rats with spinal cord injury and to explore the molecular mechanism. METHODS: Thirty-six male Sprague-Dawley rats, of SPF grade were provided by Laboratory Animal Center of Guangxi Medical University. The lentiviral vector system was prepared and transfected into spinal cord injured rats. Thirty-six rat models of spinal cord injury were established by modified Allen's method. Basso Beattie Bresnahan scores were performed. Rats were randomly divided into normal control, modeling (LV-ctrl plus spinal cord injury), overexpression (spinal cord injury plus LV-miRNA-136-5 p), and inhibition (spinal cord injury plus LV-sponge) groups (n=9/group). Seven days before surgery and the day of surgery, the overexpression and inhibition groups were continuously injected with the lentivirus suspension into the injured area, and the normal control and modeling groups were injected with the same amount of normal saline. Three rats were sacrificed at 1, 3 and 7 days, and blood and spinal cord tissues were taken. The levels of interleukin-1β, interleukion-6 and interferon-α in rat serum were determined by ELISA. The expression of NF-κB protein was detected by western blot assay and double immunofluorescence. RESULTS AND CONCLUSION: (1) There was no significant difference in preoperative Basso Beattie Bresnahan scores (P＞ 0.05). In the modeling group, the rats showed prone walking, vary degrees of urinary retention, and spinal shock, with complete loss of function of both hind limbs and muscle strength of 0. (2) Compared with the normal control group, the levels of inflammatory factors in the other groups were increased significantly (P ＜ 0.05). The expression levels of inflammatory factors were highest in the overexpression group, followed by modeling group, and lowest in the inhibition group. (3) Results of western blot assay and double immunofluorescence showed that the expression level of NF-κB protein in the modeling, overexpression and inhibition groups was significantly higher than that in the normal control group (P ＜ 0.05), and the level was highest in the overexpression group. (4) In summary, miRNA-136-5 p can affect inflammatory factors and NF-κB in rats with acute spinal cord injury.

BACKGROUND: Change of microenvironment after acute spinal cord injury is the main factor causing secondary injury, so it is of great significance to investigate the changes of microenvironment after acute spinal cord injury for clinical diagnosis and treatment. OBJECTIVE: To investigate the expression levels and clinical significance of interleukin-6, brain derived neurotrophic factor, basic fibroblast growth factor, neurotrophin-3 and neurotrophin-4 in peripheral blood within 48 hours after acute spinal cord injury. METHODS: Twenty-nine patients with acute spinal cord injury admitted at the Department of Spinal Osteopathia, the First Affiliated Hospital of Guangxi Medical University from October 2016 to June 2018 were enrolled, and were divided into two groups according to American Spinal Injury Association impairment scale: complete spinal cord injury (n=11) and incomplete spinal cord injury (n=18). Thirteen patients with avascular necrosis of the femoral head were selected as controls. The expression levels of interleukin-6, brain derived neurotrophic factor, basic fibroblast growth factor, neurotrophin-3 and neurotrophin-4 in peripheral blood of 42 patients were determined by ELISA and compared. RESULTS AND CONCLUSION: The ELISA results showed that the expression levels of interleukin-6, brain derived neurotrophic factor, basic fibroblast growth factor, neurotrophin-3 and neurotrophin-4 in peripheral blood in the spinal cord injury group were significantly higher than those in the control group (P ＜ 0.05). The expression levels of all above cytokines in the complete spinal cord injury group were significantly higher than those in the incomplete spinal cord injury group (P ＜ 0.05). In summary, increased expression of interleukin-6, brain derived neurotrophic factor, basic fibroblast growth factor, neurotrophin-3, neurotrophin-4 after acute spinal cord injury indicates that it may participate in the important pathophysiological process after acute spinal cord injury.