The miRNA and mRNA Changes in Rat Hippocampi after Chronic Constriction Injury

Abstract

Objective: We elaborated the rat hippocampi in order to assess for central nervous system changes following a peripheral neuropathic injury. Design, SettingSubjects: We examined the gene changes in the hippocampi of chronic constriction injury (CCI) rats with TaqMan® low-density array analysis (TLDA) and quantitative real-time polymerase chain reaction (qRT-PCR) of miR-125b, -132, and messenger RNAs (mRNAs) of neuropeptide Y, brain-derived neural factor, N-methyl-D-aspartate glutamate 2A receptor, gamma-aminobutyric acid A a1 receptor, gamma-aminobutyric acid A b1 receptor, gamma-aminobutyric acid B b2 receptor, serotonin 1A receptor, serotonin 2A receptor, serotonin 2C receptor, and serotonin 3A receptor on days 0, 7, and 15 after surgery. Interventions: None. Outcome Measures: Two behavioral tests (thermal and mechanical stimulation tests) were performed three times at 5-minute intervals to assess pain thresholds. MicroRNA (miRNA) changes were examined by TLDA. mRNA changes were examined by qRT-PCR. Statistical significance was determined by Tukey-Kramer's method and paired t-test. Results: All rats showed mechanical and thermal hypersensitivity on the ipsilateral side. Out of 373 miRNAs analyzed, 237 were expressed, and 51 changed their expressions after CCI. By TLDA, cluster analysis found obvious miRNA changes on day 7 that tended to recover by day 15. For miR-125b, the relative expression decreased to 0.70±0.30 at day 7 and recovered to 1.65±0.19 at day 15. The miR-132 relative expressions were 0.69±0.30 and 0.70±0.15, respectively. The mRNA changes followed the miRNA changes. Conclusions: Our results showed that the peripheral nerve injury altered rat hippocampal miRNA. Wiley Periodicals, Inc.