ABSTRACT
STUDY DESIGN: We investigated microRNA (miRNA) expression after spinal cord injury (SCI) in mice. OBJECTIVES: The recent discovery of miRNAs suggests a novel regulatory control over gene expression during plant and animal development. MiRNAs are short noncoding RNAs that suppress the translation of target genes by binding to their mRNAs, and play a central role in gene regulation in health and disease. The purpose of this study was to examine miRNA expression after SCI. SETTING: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University. METHODS: We examined the expression of miRNA (miR)-223 and miR-124a in a mouse model at 6 h, 12 h, 1 day, 3 days and 7 days after SCI using quantitative PCR. The miRNA expression was confirmed by in situ hybridization. RESULTS: Quantitative PCR revealed two peaks of miR-223 expression at 6 and 12 h and 3 days after SCI. MiR-124a expression decreased significantly from 1 day to 7 days after SCI. In situ hybridization demonstrated the presence of miR-223 around the injured site. However, miR-124a, which was present in the normal spinal cord, was not observed at the injured site. CONCLUSION: Our results indicate a time-dependent expression pattern of miR-223 and miR-124a in a mouse model of SCI. In this study, the time course of miRNA-223 expression may be related to inflammatory responses after SCI, and the time course of decreased miR-124a expression may reflect cell death.
Subject(s)
MicroRNAs/biosynthesis , Spinal Cord Injuries/metabolism , Animals , Cell Death/physiology , In Situ Hybridization , Male , Mice , Mice, Inbred C57BL , Nerve Regeneration/physiology , Oligonucleotide Array Sequence Analysis , Reverse Transcriptase Polymerase Chain Reaction , Spinal Cord/physiologyABSTRACT
Rabbits were inoculated with a suspension of VX2 carcinoma cells in the liver, and mitomycin C was given via the hepatic artery or the portal vein for a study of the anticancer effects. Twenty-eight rabbits were killed for preliminary study at 1 h or 1, 3, 7, 9, 12, or 14 days after the inoculation. Another 36 rabbits were divided into three groups. Groups A and B were given the agent (0.5 mg/kg), 1 h after the inoculation and on Days 2, 4, 6, and 8, into the common hepatic artery or the splenic vein, respectively. Group C was not treated after inoculation. The mean numbers of cancer nodules per rabbit in Groups A, B, and C were 11.9, 36.4, and 83.4, respectively, at 12 days after inoculation. The number of cancer nodules of Group A was smallest (P less than 0.025, F test). The means of the total cross-sectional area of tumor nodules in Groups A, B, and C were 32.7, 79.7, and 217.3 mm2, respectively. The total cross-sectional area of the cancer nodules of Group A was smallest (P less than 0.05, F test). These results suggest that the anticancer agents given via the hepatic artery had better effects on early (small) metastatic liver tumor than those via the portal vein.
