The Preventive Effect Of Se-Enriched Lactobacillus On Urolithiasis With Overabundance Oxalic Acid In Canine

The incidence of calcium oxalate stone in dogs is rising gradually. It has become one of the most common clinical calculus. At the same time, calcium oxalate stones are different from other types of stones, once formed, removed hardly. So how to prevent the formation of calcium oxalate stone has an important significance. There are two reasons for the formation of calcium oxalate, one is the dietary contain too much oxalate which can caused huperoxaluria, another is oxidative damage of renal epithelial cells which promotes the crystal aggregation and adhesion to epithelial cells. Thus, we can prevent the formation of hyperoxaluria by reducing the amount of oxalic acid from food. At the same time, the renal epithelial cell injury can be reduced through increasing the antioxidant capacity. A combination of both, so as to achieve the purpose of preventing the formation of calcium oxalate calculus. Some recent studies show that some lactic acid bacteria have the ability to degrade oxalic acid and oxalic acid degrading enzyme gene has been isolated from lactic acid bacteria. Selenium is an essential trace element for animals and human. Its function includes improving immunity, preventing cancer, resisting free radicals, postponing aging, detoxification from some heavy metals, and preventing some local epidemic etc. Using selenium can improve the body’s antioxidant capacity, so as to prevent renal epithelial cell injury.In this experiment, we added selenium to the culture-medium during the fermentation of lactic acid bacteria. Finally we acquire Se-enriched Lactobacillus. Unlike other Se-enriched Lactobacillus, the Se-enriched Lactobacillus which we cultured has the ability to decompose oxalic acid. Then feeding the Se-enriched Lactobacillus to overabundance oxalic acid dogs, we try to study the mechanism that how Se-enriched Lactobacillus can to prevent the formation of calcium oxalate stones. At present, only a few reports are about using the Se-enriched lactobacillus to prevent the formation of calcium oxalate stone.1. Culture Conditions Optimization of Selenium-enriched LactobacillusUsing Lactococcus subsp. latic as probiotics strains, we added inorganic Se4+ into culture-medium. Selenium-enriched probiotics is produced by cultivation, and optimizing culture conditions of Selenium-enriched probiotics. By screening, the optimum culture condition of Selenium-enriched probiotics is that, adding inorganic-selenium concentration of Sμg-ml-1 at the medium, Inoculation volume:5%, cultivated temperature:40℃, pH 6.4, cultivated time:36h. At last, selenium-enriched LAB was cultured. Selenium content in lactic acid bacteria is 3.91μg-ml-1, Selenium conversion rate is about 76.23%, the colony forming units of Lactobacillus acidophilus in the product is 10.58 lgCFU·mL-1.2. The preventive effect of Se-enriched Lactobacillus on urolithiasis with overabundance oxalic acid in canineTwenty local dogs were randomly allotted to group A, B, C, D,E. Group A was designed as control group and only fed with commercial canine food,0.5% oxalate was provided in group B,0.5% oxalate+organic selenium was provided in group C,0.5% oxalate+Lactococcus subsp. Latic was provided in group D, and 0.5% oxalate+ Selenium-enriched Lactobacillus was provided in group E. On day 15 and 30, biochemical parameters of blood and urine were measured, and the content of selenium in blood was also measured. The results showed that during the experiment, on day 15 and 30, the experimental group could prevent urine pH value from decreasing (P<0.05), group E had the best effect which had no significantly difference from the control group (P>0.05). On day 15 and 30, Selenium-enriched Lactobacillus could significantly prevent elevated urine oxalate (P<0.05). On day 15 and 30, the test group could prevent the increasing of blood creatinine and urea nitrogen, the same as urine creatinine and urea nitrogen, but the difference was not significant (P>0.05). On day 30, Selenium-enriched Lactobacillus could prevent blood calcium from decreasing, and the difference was significant (P<0.05). On day 15 and 30, group E could significantly prevent urinary calcium increasing (P<0.05). The 15d and 30d, the selenium content of group C and E increased significantly (P<0.05). In experiment 30d, we measured the antioxidant capacity of renal tissue and blood. In experimental group, SOD in serum and kidney tissue, GSH-PX in blood and renal tissue, CAT in serum and renal tissue were significantly higher than that of oxalic acid group (P<0.05). The content of MDA in serum and renal tissue for the test group were significantly lower than that of oxalic acid group (P<0.05). The conclusion is Se-enriched Lactobacillus can significantly enhance the decomposition of oxalate, and improve the body’s antioxidant capacity, so as to achieve the objective that preventing the form of calcium oxalate stones.