[Bifidobacterium bifidum TMC3115 Promotes Early Life Intestinal Microbiota Building to Alleviate Symptoms of Inflammatory Bowel Disease].

Objective: To investigate the effects of using Bifidobacterium bifidum TMC3115 in early life on intestinal microbiota and immune functions and the long-term impact on inflammatory bowel disease. Methods: Fourteen pregnant BALB/c mice were purchased and 84 newborn BALB/c mice were subsequently obtained. Then, the newborn mice were randomly assigned to a normal saline (NS) group and a TMC3115 group, given via oral gavage normal saline and TMC3115, respectively, at a daily volume of 0.2 mL for each mouse. About 42 mice were assigned to each group. The gavage was stopped after 3 weeks. At this point, half of the mice in each group were sacrificed, and then the remaining mice in each group were randomly divided into NS-water group, NS-DSS group, TMC3115-water group, and TMC3115-DSS group, with about 10 mice in each group. The mice were given regular feed until the end of week 6 when they were given 3% dextran sulphate sodium (DSS) ad libitum for 4 days to establish the enteritis model, while the non-modeling groups were given pure water ad libitum. The experiment ended after 6 weeks and 4 days. The weekly body mass changes of the mice were documented. The intestinal tissue at the end of the experiment and the fecal samples, spleen and serum of the mice at 3 weeks and at the end of the experiment were collected to determine the pathology scores of colonic inflammation, the composition of fecal gut microbiota, spleen organ index and the mass concentration of serum cytokines. Results: 1) At the end of the experiment, the inflammatory pathology score was significantly lower in the TMC3115-DSS group compared with that of the Saline-DSS group ( P<0.05), with less disruption of colonic crypt structures and other structures, less inflammatory infiltration, and more intact epithelial structures. 2) At 3 weeks, in comparison with those of the NS group, the relative abundance of Bifidobacteriumwas significantly higher in the feces of the TMC3115 ( P<0.05), the relative abundance of both Enterococcusand Staphylococcuswas lower ( P<0.05), the splenic organ index was significantly higher ( P<0.05), and interleukin (IL)-10 was significantly decreased ( P<0.05), while there was no significant change in IL-6 or TNF-α ( P>0.05). At the end of the experiment, in comparison with those of the NS-DSS group that undergone DSS induction, the TMC3115-DSS group had reduced relative abundance of Staphylococcus, Staphylococcus tumefaciens and Escherichia/ Shigellain the feces ( P<0.05), while the splenic organ index was significantly higher ( P<0.05), and there were no significant changes in IL-6 or TNF-α ( P>0.05). Conclusion: The use of TMC3115 in early life promotes the construction of gut microbiota in neonatal mice, thereby producing a long-term effect that alleviates colitis in mice, but the mechanisms involved are still not fully understood.

[Establishment of a real-time PCR assay for simultaneously detecting human BKV and CMV DNA and its application in renal transplantation recipients].

To establish a fluorescent quantitative PCR method (FQ-PCR) with TaqMan probe for simultaneous detection of polyomavirus (BKV) and cytomegalovirus (CMV) and to evaluate its clinical application in the renal transplantation recipients. The conservative sequences of BKV and CMV were targeted and amplified by nested PCR technique. The PCR products were cloned into the plasmids pcDNA3. 1(+). The recombinant plasmid containing target sequences of BKV and CMV were constructed as external standards. The TaqMan-based assay was optimized. For evaluating the assay, the sensitivity was determinated by diluted standard (5 X 103-10icopies/mL), and the specificity was verified by negative control and positive control, and the precision was assessed by intra-assay coefficient of variation (ICV) through detecting standard repeatedly (20 times). A total of 480 blood samples of renal transplantation recipients were used to detect BKV and CMV DNA simultaneously with FQ-PCR, and the concentrations of FK506 were measured by ELISA. The association of DNA copy and concentrations of FK506 was analyzed. The cloned target BKV and CMV DNA was confirmed by sequencing and analysis. The sensitivity of the FQ-PCR assay reached 5 X 103 copies/ml in detecting BKV or CMV DNA. Control DNA verified the assay specifically detecting target DNA. The precision of the assay to quantif target DNA copies was acceptable (Intra-assay CV was 3.44% for BKV and 2.23% for CMV; Inter-assay CV was 4. 98% for BKV and 3.76% for CMV;). Of 480 samples, 130 samples (27. 08%) were CMV DNA positive, significantly higher than the BKV DNA positive (13.33%, 64/480, P<0.05). The positive BKV or CMV DNA was found to be associated with high concentrations of FK506 (P<0. 05). In conclusion, the developed real-time PCR assay for detecting both CMV and BKV DNA simultaneously was s high sensitive, precise and time-effectiveand could be applied in the monitoring of the CMV and BKV infection in the renal transplantation recipients.