To study the effect of hyperbaric
oxygen intervention on the microenvironment of nerve regeneration after
spinal cord injury modeling and to explore the possible mechanism of nerve regeneration and functional recovery in rats with
spinal cord injury. In 98 adult female SD rats, 90 successful models were obtained, which were divided into
sham group,
spinal cord injury group and hyperbaric
oxygen group using randomized block method, 30/group.
Spinal cord injury rat model was established in accordance with the modified Allen method. Motor function was assessed at the time points of before modeling, one day, three days, one week, two weeks, three weeks and four weeks after modeling respectively by BBB rating, inclined plane test and improved Tarlov score. At 3 days after modeling, apoptosis of neuronal cells in
spinal cord injury region in experimental group was detected by TUNEL method; gene and
protein expression of MMP9/2 in
spinal cord injury and surrounding tissues was detected by RT-PCR and Western blot assay. At 4 weeks after modeling, histopathological morphological changes in
spinal cord injury were observed by HE staining;
fluorogold retrograde tracing was used to observe the regeneration and distribution of spinal cord nerve fibers and axon regeneration was observed by TEM. The three motor function scores in hyperbaric
oxygen group at each time point after two weeks of treatment were significantly increased compared with
spinal cord injury group (P < 0.05). At 3 d after modeling, apoptosis index in hyperbaric
oxygen group were significantly lower than those in
spinal cord injury group (P < 0.05). At 72 h after modeling, compared with
spinal cord injury group, MMP9/2 gene and
protein expression in hyperbaric
oxygen group was significantly lower (P < 0.05). At four weeks after modeling,
fluorogold positive nerve fibers were the most
sham group, followed by hyperbaric
oxygen group and
spinal cord injury group in order; the differences among the groups were statistically significant (P < 0.05). Under TEM, newborn unmyelinated and myelinated nerve fibers could be observed in the middle cross-section in the
sham group and hyperbaric
oxygen group; unmyelinated and myelinated nerve fibers in hyperbaric
oxygen group were more than those in
spinal cord injury group.
Hyperbaric oxygen therapy played a protective effect on
spinal cord injury through reducing apoptosis of neuronal cells and expression of MMP9/2 gene and
protein in rats with
spinal cord injury.