title: A real-time quantitative PCR comparative study between rat optic and sciatic nerves: determination of neuregulin-1 mRNA levels.
abstract: Injured axons from peripheral nervous system (PNS) possess the ability to regenerate. In contrast, regeneration of injured axons does not occur in the central nervous system (CNS) or occurs to a limited extent. Previous works have shown that rat sciatic nerve conditioned medium (CM) produced PC12 cells neuronal-like differentiation and neurite outgrowth. In the present work, we compared the expression of neuregulin-1s (NRG-1s) from rat sciatic and optic nerves as members of the PNS and CNS, respectively. Sciatic nerve CM showed a higher neurotrophic activity on PC12 cells than rat optic nerve CM. RT-PCR analysis verified the presence of all three types of NRG-1 mRNAs and their receptors in both types of nerves. Real-time quantitative PCR (QPCR) assays showed that the relative expression levels of all three types of NRG-1 mRNAs were higher in optic nerves than in sciatic nerves. Eleven-day cultured optic nerves showed an increased in NDF and SMDF when compared to freshly isolated optic nerves, whereas GGF decreased. However, 11-day-cultured sciatic nerves only showed an increase in SMDF mRNA. Western blots corroborated the differences in NRG-1 expression profile for both types of nerves and their CMs. Incubation of both CMs with the anti-pan-NRG-1 antibody showed that the neurotrophic activity of the optic nerve CM increased, whereas the sciatic nerve CM remained unchanged. These results indicated that different NRG-1 levels are expressed upon nerve degeneration and the balance between those levels and other neurotrophic factors could have an important role on nerve regeneration.
authors.affiliation: Instituto de Estudios Avanzados (IDEA), Apartado 17606, Caracas 1015-A, Miranda 1080, Venezuela. jmartien@reaccium.ve
authors.forename: J C
authors.initials: JC
authors.lastname: Martínez
authors.forename: C
authors.initials: C
authors.lastname: Malavé
authors.forename: I
authors.initials: I
authors.lastname: Bosch
authors.forename: C
authors.initials: C
authors.lastname: Castillo
authors.forename: J
authors.initials: J
authors.lastname: Núñez
authors.forename: G M
authors.initials: GM
authors.lastname: Villegas
authors.forename: R
authors.initials: R
authors.lastname: Villegas
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D015153:Blotting, Western / Q000379:methods; D002454:Cell Differentiation / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006023:Glycoproteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D020890:Neuregulin-1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D009900:Optic Nerve / Q000378:metabolism*; D009924:Organ Culture Techniques; D016716:PC12 Cells; D020033:Protein Isoforms / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018719:Erb-b2 Receptor Tyrosine Kinases; D049349:Receptors, Lysosphingolipid / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012584:Sciatic Nerve / Q000378:metabolism*
chemical_list: D000906:Antibodies; D017077:Culture Media, Conditioned; D006023:Glycoproteins; D020890:Neuregulin-1; D020033:Protein Isoforms; D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases; D049349:Receptors, Lysosphingolipid; C483804:Erbb2 protein, rat