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.

Validation of DNA Damage Progression with Days after Single Exposure of Sublethal Dosage of Electron Beam Radiation.

The aim of this study was to asses the DNA damage progression with days after single exposure of 6Gy electron beam radiation (EBR). Molecular DNA damage in lymphocytes of mice was assessed using alkaline comet assay and in bone marrow cells by micronucleus assay. In comet assay %DNA in tail, Comet length, Olive Tail Moment (OTM) served as a measure of DNA damage and in micronucleus test, frequency of micronucleus formation in bone marrow cells was measured to evaluate the DNA damage. The experiment was performed by taking 24 healthy Swiss albino mice with body weight 30+5g. The animals were grouped into four. Group1 served as control, Group 2, 3 and 4 were irradiated by 6Gy EBR. Animals of Group 2, 3 and 4 were sacrificed on 5th, 10th and 15th day post irradiation respectively. The comet assay procedure was carried out for all these groups by using lymphocytes separated from EDTA treated blood. The micronucleus test was performed in bone marrow cells (PCE-Poly chromatic erythrocytes, NCE-normochromatic erythrocytes). The slides prepared for this were scored for the measure of DNA damage. The results showed all comet parameter were significantly (P<0.05) affected by prolonging the post irradiation days from zero (control) to 5, 10 and 15. There was an alteration found in the PCE/PCE+NCE ratio in irradiated mice. A linear increase in the micronucleus formation was observed in post irradiated days. These results conclude a progression in DNA damage with days, post irradiation.