Related Experiment Video
Updated: Jul 11, 2026
Bioprintable Alginate/Gelatin Hydrogel 3D In Vitro Model Systems Induce Cell Spheroid Formation
Published on: July 2, 2018
Safety issues of Lactobacillus bulgaricus with respect to human gelatinases in vitro
Iva Stamatova1, Jukka H Meurman, Kirsti Kari
1Institute of Dentistry, University of Helsinki, Helsinki, Finland. iva.stamatova@avb.bg
Abstract:
In oral medicine and dentistry probiotics have shown promising results in controlling dental diseases and yeast infections. This study was made to investigate the effect of eight strains of Lactobacillus bulgaricus and their effects on human matrix metalloproteinase-9 (MMP-9). The hypothesis was that these bacteria used in yoghurt production for centuries are not proteolytic and thus can be safely used in the development of probiotic preparations. Bacterial cell fractions and supernatant specimens were prepared and studied with gelatinase zymography and MMP-9 activation was assessed by immunoblotting. The effect of synthetic MMP inhibitors and a serine protease inhibitor (Pefabloc) on bacterial proteinases was studied with zymography. The results showed very low gelatinolytic activity. There was a slight difference between the supernatant and cell fractions so that the supernatant specimens produced weak gelatinolytic bands in zymography while hardly anything was seen in the cell fraction series. The tested synthetic MMP inhibitors and Pefabloc did not affect the proteolytic activity of the lactobacilli strains. The lactobacilli did not seem to induce the conversion of proMMP-9 to its active form. Consequently, our study hypothesis was confirmed and the studied Lactobacillus strains are not likely to degrade host tissue components.
Insights
Probiotic Lactobacillus bulgaricus strains show minimal proteolytic activity, suggesting their safety for oral health applications. These bacteria do not appear to degrade human tissue components like matrix metalloproteinase-9 (MMP-9).
Area of Science:
- Oral Medicine
- Microbiology
- Biochemistry
Background:
- Probiotics, particularly Lactobacillus strains, show potential in managing oral diseases and infections.
- Matrix metalloproteinase-9 (MMP-9) plays a role in tissue degradation and is a target for therapeutic intervention.
Purpose of the Study:
- To investigate the proteolytic activity of eight Lactobacillus bulgaricus strains.
- To assess the effect of these strains on human matrix metalloproteinase-9 (MMP-9) activation.
- To evaluate the safety of these Lactobacillus strains for probiotic development in oral applications.
Main Methods:
- Bacterial cell fractions and supernatants were prepared from eight Lactobacillus bulgaricus strains.
- Gelatinase zymography was used to assess gelatinolytic activity.
- Immunoblotting was employed to detect MMP-9 activation.
- The impact of MMP inhibitors and a serine protease inhibitor on bacterial proteinases was examined.
Main Results:
- Lactobacillus bulgaricus strains exhibited very low gelatinolytic activity.
- Supernatant fractions showed weak gelatinolytic bands, while cell fractions showed minimal activity.
- Tested MMP inhibitors and Pefabloc did not inhibit the proteolytic activity of the lactobacilli.
- The lactobacilli strains did not induce the activation of proMMP-9 to its active form.
Conclusions:
- The hypothesis that Lactobacillus bulgaricus strains are not proteolytic was confirmed.
- These strains are unlikely to degrade host tissue components, supporting their safety for oral probiotic development.
- Further research can explore the therapeutic potential of these specific Lactobacillus strains in dentistry.
