Figure 1. Expression and regulation of MT1-MMP by TGF-ß1 and BMP-2 in odontoblasts and pulp tissue. (A) Total RNA from native and cultured odontoblasts (ObN and ObC, respectively) and native and cultured pulp tissue (PN and PC, respectively) were transcribed into cDNA. MT1-MMP mRNA and 18S ribosomal RNA were amplified by PCR. Products were fractionated on a 1.5% agarose gel containing 1 µg/mL ethidium bromide and were photographed. PCR was repeated 4 times. A 395-bp MT1-MMP transcript was amplified from native and cultured odontoblasts and pulp tissue, respectively. In nested PCR amplifications, a 267-bp product was amplified from all samples, confirming the identity of MT1-MMP. In the negative control (NCtr), where template was not added, no product was amplified. 18S ribosomal transcripts, amplified from the samples, served as the endogenous control. (B) Odontoblasts and pulp tissue (n = 6 for all samples) were treated without (Ctr) or with TGF-ß1 (T), BMP-2 (B), or both growth factors combined (T+B). MT1-MMP and 28S ribosomal RNA were analyzed by RPA. The bands were scanned, and the relative MT1-MMP levels in each group were calculated based on the 28S standard values. (C-D) A mean and standard error of the mean (SEM) of the relative MT1-MMP mRNA expression in odontoblasts (C) and pulp tissue (D) (n = 6 in all groups). 100 ng/mL BMP-2 decreased the expression of MT1-MMP mRNA by 66% when compared with controls (**: p = 0.006, ANOVA with LSD test), while with 1 ng/mL TGF-ß1, alone or in combination with BMP-2, only a moderate 36-40% decrease was detected, and this difference was not statistically significant (C). In the pulp tissue, a similar but less marked non-significant reduction in MT1-MMP expression was observed (D).
