Date of Award

5-2009

Document Type

Thesis

Degree Name

Master of Dental Science (MDS)

Program

Periodontology

Research Advisor

David A. Tipton, D.D.S., Ph.D.

Committee

David A. Tipton, D.D.S., Ph.D. Pradeep Chitra Adatrow, D.D.S., M.S.D., M.P.H. Jegdish P. Babu, Ph.D. Swati Y. Rawal, B.D.S., M.D.S., M.S.

Abstract

Methamphetamine (METH) abuse is associated with "METH mouth" characterized by rampant caries and periodontitis. Matrix metalloproteinases (MMPs) produced by gingival fibroblasts degrade the extracellular matrix (ECM) and play an important role in periodontitis and oral cancer metastasis. There is no information on effects of METH on fibroblast MMP production, or its role in periodontitis or tumor metastasis.

Objective: Determine effect of METH on gingival fibroblast MMP production and activity.

Methods: A human gingival fibroblast cell line was used. METH cytotoxicity was determined by measuring its effects on activity of a mitochondrial enzyme. Cells were cultured ± METH (1x10-6- ≥ 1x10-3M); MMP-2, MMP-9, TIMP-1,TIMP-2 and MMP:TIMP complexes in cell supernatants were measured by ELISA. MMP-2 activity was measured using the MMP-2 Biotrak Activity Assay System. Data were analyzed using ANOVA and Scheffe’s F procedure for post hoc comparisons.

Results: There was no significant cytotoxicity of METH at concentrations ≤ 1mM. METH > 1mM caused complete loss of viability. MMP-2, TIMP-1, -2 and MMP-2:TIMP complexes were produced constitutively; MMP-9 and MMP-9:TIMP complexes were not expressed. Approximately 25% of MMP-2 was complexed with TIMP-1 or TIMP-2. METH had no significant effect on any molecules expressed constitutively or on complexed MMP-2, and it did not induce MMP-9 or MMP-9:TIMP complexes. 1x10-5 M METH increased total MMP-2 activity (p = 0.01) and APMA-activated MMP-2 activity attributable to pro-MMP-2 (p = 0.03). METH had no effect on endogenous active MMP-2. Using pro-MMP-2 (standard from MMP-2 activity kit) treated with METH ± p-aminophenylmercuric acetate (APMA) and assayed for activity, METH directly activated MMP-2 and enhanced APMA activation of free pro-MMP-2.

Conclusions: METH may affect MMP-2 post-transcriptionally, increasing activity/activation of pro-MMP-2, rather than affecting protein levels.

DOI

10.21007/etd.cghs.2009.0090

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