Expression of Nogo-A mRNA after injury of the rat central nervous system

BACKGROUND: Nogo protein has been identified as an inhibitor of axonal growth, which was highly expressed in central nervous system; however, there are only it few studies on changes of Nogo-A expression following central nervous system injury. OBJECTIVE: To investigate the dynamic expression of Nogo-A mRNA after rat central nervous system injury. DESIGN: Randomized controlled animal study. MATERIALS: Thirty-five rats were randomly divided into two groups, normal animal group (n = 5) and model group (11 = 30). The model group was then divided into six subgroups at six time points: 12, 24 hours and 3, 9, 15, and 21 days post-injury, with Five rats in each subgroup. METHODS: The left parietal lobe of rats was contused by free-fall strike, and total RNA was extracted from the entire brain tissue. Semi-quantitative RT-PCR was used to detect Nogo-A mRNA expression, and the ratio between expression of the target gene and glyceraldehyde phosphate dehydrogenase was used to determine the relative expression level. MAIN OUTCOME MEASURES: To determine whether Nogo-A mRNA expression was higher than usual following brain injury. RESULTS: The level of Nogo-A mRNA started to increase 12 hours after injury (P < 0.05) and decreased slightly by 24 hours post-injury. Expression increased again on day 3 and reached a peak on day 9. Nogo-A mRNA expression started to decrease on day 15, and then decreased to normal levels at days 21 (P > 0.05). CONCLUSION: After injury of the central nervous system, Nogo-A may play a pivotal role in obstructing regeneration of the nerve.