Assessment of Proliferation, Clonogenic Assay, and Osteogenic Differentiation of Human Periodontal Ligament Stem Cells Following Application of Orthodontic Forces

Context: The proliferation and differentiation of human periodontal ligament stem cells (hPDLSC) into other cell types are also mediated by mechanical stresses; they might offer therapeutic benefits in tissue regeneration and angiogenesis. Objectives: The study was planned to assess the proliferation, clonogenic potential, and osteogenic differentiation of human periodontal ligament stem cells (PDLSC) following the application of light and heavy orthodontic forces. Materials and Methods: A couple forces of 50 gm (light force) were applied on the 1st premolar on the one side and 250 gm (heavy force) on the contralateral side in the upper arch of patients requiring orthodontic treatment with extraction of all 1st premolars. After 30 days, periodontal tissues were scrapped from extracted teeth for the establishment of PDLSC in vitro. PDLC from the lower premolar teeth where no orthodontic force was applied acted as the control group. Morphology, viability, proliferating rate and population doubling time, clonogenicity, and alkaline phosphatase activity were analysed. Result: The osteogenic potential was confirmed by Alizarin red staining and the expression of the osteogenic markers by qRT?PCR. The morphology, growth kinetics, potency, and osteogenic lineage characteristics inferred the application of high force reduced the proliferative ability and osteogenesis of PDLSC, though the difference was not significant. Conclusion: The established PDLSCs demonstrated their MSC?like properties based on morphology, growth kinetics, colony forming ability, and AP activity. The culture?expanded PDLSCs showed their differentiation potential into osteocytes. The application of high force reduced the proliferative ability and osteogenesis of PDLSCs, variations were not significant.differentiation

Radioprotective Properties of Chitosan on Cultured Human Lymphocytes against Electron Beam Radiation.

The radioprotective effects of naturally occurring compounds have been investigated in vitro and in vivo considering their pharmacological role in prevention and treatment of cancer. Chitosan (CS) is a naturally occurring polymer that has been increasing attention in pharmaceutical and biomedical applications because of its biocompatibility, biodegradability, nontoxicity, cationic properties and bio adhesive characters. Lymphocytes were treated with different concentrations of chitosan for the period of 2 and 24 hr. Cell viability was determined by tryphan blue dye exclusion assay, single strand DNA damage by alkaline comet assay and in vitro cytogenetic damages were evaluated by micronucleus assays. Treatment of lymphocytes with chitosan before and after the exposure to 4Gy of electron beam radiation (EBR) resulted in the reduction of percentage of tail DNA in comet from 24.06±3.92 to 6.94±1.34 and olive tail moment (OTM) was reduced from 25.34±3.09 to 10.66±0.23 at 10μg/mL concentration. The micronucleus formation in radiation control group (13.75±0.37) was significantly reduced in chitosan pretreated groups 7.63±1.02. Cells treated with chitosan at 10μg/mL showed maximum viability after exposure to EBR. Present investigation data proves the protective effect of CS against EBR induced damage in lymphocyte. However, increase in concentration above 100 μg/mL though resulted in higher protection, an increased cell toxicity was also noticed.

Modulatory effect of Allium sativum Ethanolic Extract on Cultured Human Lymphocytes.

Allium sativum (Garlic) have been known since from ancient years for its medicinal properties. It is widely used as antibacterial, antifungal, anticoagulant, anticancer, hypoglycaemicand hypocholesteromic. The aim of the present study was to assess the effect of different concentration ofethanolic extract of Allium sativum extract on cultured human lymphocytes. Cytotoxicity was assessed by tryphan blue dye exclusion assay, single strand DNA damage was studied by alkaline comet assay and apoptosis was assessed by DNA diffusion assay. The percentage of live and dead cells was counted in cell viability assay. In comet assay tail length, percentage tail DNA and olive tail movement were considered as parameters for DNA damage. In DNA diffusion assay number of apoptotic cells counted comparing the normal cell nucleus and apoptotic cell nucleus. The study was performed in 3 concentrations of Allium sativum extract, 10, 50 and 100μg/ml including untreated control group. The results showed that all the comet parameters was significantly (p<0.05) increased by the effect of Allium sativum extract, which was dose dependent. Percentage of apoptotic cells also increased with higher concentration of the garlic. These results conclude, the cytotoxicity induced by the garlic extract is directly proportional to the single strand DNA break. The increase in the DNA damage positively correlates to the number of apoptotic cells present in the culture medium.