Increased intestinal absorption of oxalate causes hyperoxaluria, a major risk factor for kidney stone disease. Intestinal colonization of recombinant probiotic bacteria expressing oxalate-degrading gene (OxdC) is an effective therapeutic option for recurrent calcium oxalate (CaOx) stone disease. Therefore, we aimed to develop food-grade probiotic L. plantarum secreting OxdC using lactococcal group II intron, Ll.LtrB and evaluate its oxalate degradation ability in vivo. Male Wistar albino rats were divided into four groups. The rats of group I received normal rat chow and drinking water. Groups II, III and IV rats received 5% potassium oxalate containing diet for 28 days. Groups III and IV rats received L. plantarum and food-grade recombinant L. plantarum respectively from 15 to 28 days. Biochemical parameters and crystalluria were analysed in 24 h urine samples. At the end of experimental period, rats were sacrificed; intestine and kidneys were dissected out for colonization studies and histopathological analysis. Herein, we found that the administration of recombinant probiotics significantly reduced the urinary oxalate, calcium, urea, and creatinine levels in rats of group IV compared to group II. Furthermore, colonization studies indicated that recombinant probiotics have gastrointestinal transit and intestinal colonization ability similar to that of wild-type bacteria. In addition, gene expression studies revealed down-regulation of OPN and KIM-1 among group IV rats. Histopathological analysis showed less evidence of nephrocalcinosis in group IV rats. In conclusion, the study demonstrates that food-grade L. plantarum secreting OxdC is capable of degrading intestinal oxalate and thereby prevent CaOx stone formation in experimental rats.

草酸盐在肠道中的吸收增加会引起高草酸尿症，这是肾结石疾病的主要危险因素。表达草酸降解基因（OxdC）的重组益生菌的肠道定植是复发性草酸钙（CaOx）结石病的有效治疗选择。因此，我们旨在使用乳球菌第II组内含子L.LtrB来开发分泌OxdC的食品级益生菌植物乳杆菌，并评估其在体内的草酸盐降解能力。将雄性Wistar白化病大鼠分为四组。第一组的大鼠接受正常的大鼠食物和饮用水。II，III和IV组的大鼠接受了含草酸钾的5％的饮食，持续28天。第三和第四组大鼠接受植物乳杆菌和食品级重组体植物乳杆菌分别为15至28天。在24小时尿液样本中分析生化参数和结晶度。实验结束时，处死大鼠。解剖出肠和肾以进行定植研究和组织病理学分析。在本文中，我们发现，与第二组相比，第四组大鼠中重组益生菌的施用显着降低了尿草酸，钙，尿素和肌酐水平。此外，定植研究表明，重组益生菌具有与野生型细菌相似的胃肠道转运和肠道定植能力。此外，基因表达研究显示OPN和KIM的下调第四组大鼠中为-1。组织病理学分析显示，IV组大鼠肾钙化病的证据较少。总之，该研究表明，食品级植物乳杆菌分泌OxdC能够降解肠道草酸盐，从而防止实验大鼠中CaOx结石的形成。