ANALYSIS OF TGF-BETA-1 GENE-EXPRESSION IN CONTUSED RAT SPINAL-CORD USING QUANTITATIVE RT-PCR

We have used northern blot analysis and quantitative reverse transcrip tion polymerase chain reaction (RT-PCR) to determine the postinjury ex pression profile of the transforming growth factor-beta 1 (TGF-beta 1) gene in the contused rat spinal cord, Spectrophotometric estimates of total sample RNA and quantitative analyses of cyclophilin mRNA using RT-PCR served as controls for comparisons between samples, No changes in cyclophilin gene expression were found at any postinjury survival t imes, The results of the TGF-beta 1 analyses, which were carried out o n spinal cord samples taken at postinjury intervals ranging from 6 h t o 10 days, show that the amount of TGF-beta 1 mRNA present in spinal c ord increases rapidly following injury, reaching maximum levels 7 days postinjury. Unoperated control samples contained approximately 2 x 10 (8) molecules of TGF-beta 1 mRNA/0.5 mu g total RNA. By 1 day postinju ry, the amount of TGF-beta 1 mRNA in the cord had increased by a facto r of 2.5 to 5 x 10(8) molecules/0.5 mu g total RNA, At 7 days postinju ry, there were approximately 15 x 10(8) molecules of TGF-beta 1 mRNA/0 .5 mu g total RNA. By 10 days postinjury the amount of TGF-beta 1 mRNA present in the spinal cord had declined to 8 x 10(8) molecules of TGF -beta 1 mRNA/0.5 mu g total RNA, a value similar to that observed at 3 days postinjury, The roles that TGF-beta 1 might play in modifying ce llular responses in injured spinal cord are discussed.