title: [Effect of dopamine on the activity of matrix metalloproteinases and degradation of dentin collagen].
abstract: OBJECTIVE
  To investigate the inhibition effect of dopamine on the activity of matrix metalloproteinases (MMP) and the effect of dopamine on degradation of dentin collagen for its potential use in caries treatment and dentin adhesive.
  
  
  METHODS
  In the experiment of MMP activity test, 2.0 g/L dopamine + 1.0 g/L highly purified collagenase type VIII from Clostridium histolyticum served as the experimental group, and deionized water + 1.0 g/L highly purified collagenase type VIII from Clostridium histolyticum served as the negative control group, and 2% chlorhexidine + 1.0 g/L highly purified collagenase type VIII from Clostridium histolyticum served as the positive control group, and the mixture volume ratio of the two ingredients in every group was 1:9. After 15 minutes, the enzyme activity of each sample was tested by MMP activity colerimetric quantitative detection kits, and the test was repeated 5 times in each group. In the experiment of collagen degradation, the dentin slices were demineralized with 37% phosphoric acid for 1 min. In sequence, 2 dentin slices were used to observe the morphology, and the remaining 30 dentine slices were randomly divided into three groups (n = 10) according to random number table: the negative control ones were stored in 100 µl deionized water and 900 µl collagenase (7 days, 37 °C), the positive control ones were stored in 100 µl chlorhexidine and 900 µl collagenase (7 days, 37 °C) and the experimental specimens were stored in 100 µl dopamine and 900 µl collagenase (7 days, 37 °C). The degraded collagen was investigated by assaying hydroxyproline. The framework of collagen was evaluated with field emission scanning electron microscope (FE-SEM).
  
  
  RESULTS
  The statistical results of completely random design ANOVA showed that the MMP activity and the amount of degraded collagen of the negative control group [(0.089 ± 0.011) µmol · min⁻¹ · mg⁻¹ and (2 837 ± 201) µg/cm²] were significantly higher than those of the positive control group [(0.038 ± 0.006) µmol · min⁻¹ · mg⁻¹ and (1 288 ± 172) µg/cm²] and the experimental group [(0.030 ± 0.009) µmol · min⁻¹ · mg⁻¹ and (1 389 ± 255) µg/cm²] (P < 0.05). SEM observation indicated that the structural integrity of the collagen network on dentin still existed in experiment samples and positive control groups, however, collagen fibrils were destructed and the structural integrity disappeared in the negative control groups.
  
  
  CONCLUSIONS
  Dopamine may inhibit MMP activity and reduce the amount of degraded collagen.
authors.affiliation: Department of Prosthodontics, Stomatologic Hospital and College, Anhui Medical University & Key Laboratory of Oral Diseases Research of Anhui Province, Hefei 230032, China.
authors.forename: Qiangjian
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Department of Prosthodontics, Stomatologic Hospital and College, Anhui Medical University & Key Laboratory of Oral Diseases Research of Anhui Province, Hefei 230032, China; Email: ql-li@126.com.
authors.forename: Quanli
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Prosthodontics, Stomatologic Hospital and College, Anhui Medical University & Key Laboratory of Oral Diseases Research of Anhui Province, Hefei 230032, China.
authors.forename: Jialong
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Prosthodontics, Stomatologic Hospital and College, Anhui Medical University & Key Laboratory of Oral Diseases Research of Anhui Province, Hefei 230032, China.
authors.forename: Weibo
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Prosthodontics, Stomatologic Hospital and College, Anhui Medical University & Key Laboratory of Oral Diseases Research of Anhui Province, Hefei 230032, China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Prosthodontics, Stomatologic Hospital and College, Anhui Medical University & Key Laboratory of Oral Diseases Research of Anhui Province, Hefei 230032, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Cao
mesh_terms: D002710:Chlorhexidine / Q000494:pharmacology; D003094:Collagen / Q000187:drug effects*; D003731:Dental Caries / Q000628:therapy; D003804:Dentin / Q000187:drug effects* / Q000378:metabolism; D017220:Dentin-Bonding Agents; D004298:Dopamine / Q000494:pharmacology*; D015259:Dopamine Agents / Q000494:pharmacology*; D005109:Extracellular Matrix; D006801:Humans; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D003012:Microbial Collagenase / Q000494:pharmacology; D010756:Phosphoric Acids / Q000494:pharmacology
chemical_list: D017220:Dentin-Bonding Agents; D015259:Dopamine Agents; D010756:Phosphoric Acids; D003094:Collagen; C030242:phosphoric acid; D020782:Matrix Metalloproteinases; D003012:Microbial Collagenase; D002710:Chlorhexidine; D004298:Dopamine