Study the Effect of Locally isolated Lactobacillus acidophilus and its components as anticancer in vivo
Abstract
: The aim of this study was to investigate the role of Lactobacilli as a probiotic in colon cancer treatment in rats. Accordingly 29 isolates of Lactobacilli was obtained from 11 samples of feces of newborns. As well as isolating and diagnosis one isolate of Lactobacilli from standard yoghurt named (canon) which used as control for acid and bile salt tolerance. Screening of isolate according to its ability of acid resistance, showed that six isolates were able to stand in pH3.5 for 90 min. The number of living cells were 1.73×105 to 6.3×105 CFU/ml. Accordingly the number of living cells of other isolates were significantly decreased after 90 min incubation in MRS broth with pH3.5 . The isolate from standard yoghurt did not revealed high resistances to acidity since the living cells were decreased with a rrange equal about to one logarithmic cycle or more. This behaviors is important from static point of view which indicates no high acidity resistance.
The isolates which appear high acidity resistance were selected to test its resistance to bile salts. Lactobacillus acidophilusone of diagnosed isolates, appeared high resistance to bile salts, since it was the most efficient isolate among the selected isolate in its high resistance to bile salts. While for Lactobacillus delbrueckii ssp bulgaricus which was used for comparison with the other isolates, revealed no resistance for bile salts since the number Components of Lactobacillus acidophilus were separated. Colon cancer was induced in rats using Azoxymethane (AOM) at 15mg/Kg (animal body weight) by adding methyl group to guanine (O6- methyl guanine). Two restriction enzymes were used to detect the methylation. The first HpaII which is sensitive to presence of methyl group and the second is MspI which is resistant to methyl group so the samples treated with former will give a clear band of methylated DNA in gel electrophoresis while MspI will give diffused band when the DNA is methylated. The prophylactic effect (pretreatment) and the therapeutic effect (post- treatment) of Lb. acidophilus cells and its separated components was studied in vivo on the molecular level, DNA was extracted from rat colon and treated for methylation. The results revealed that the DNA extracted from treated animal showed smear in gel electrophoresis after digestion with HpaII which means that lactobacillus could modulate the DNA methylation, in contrast to positive control group which had specific DNA methylation band which indicates the presence of methyl group in the DNA of this animals.
