Objective To explore the rule of transportation in extracellular space (ECS) and the changes induced by the external stimulation with tracer-based MRI.Methods Thirty two mature Sprague Dawley rats were randomly divided into four groups,i.e.caudate nucleus-control (Cc) group,thalamus-control (Tc) group,caudate nucleus-moving (Cm) group and thalamus pain stimulation (Tp) group.The rats were anesthetized and a series of MR scanning were performed before and after the injection of Gd-DTPA in ECS of caudate nucleus and thalamus until the intensity of Gd-DTPA was invisible.Half-life of Gd-DTPA in ECS was calculated and analyzed with t-test.Results Gd DTPA in caudate nucleus was transported to the ipsilateral cortices away from the injection points,which only distributed on site in the thalamus.The transportation between the two partitions was not observed.The half-life of Tc group ([49.93±2.11] min) was significantly shorter than that of Cc group ([104.30±54.12];t=2.839,P＜0.05),no difference was observed between the Cm group ([113.42±47.32]min) and Cc group (t=0.359,P＞0.05),while half-life of Tp group ([109.40±10.33]min) was significantly longer than that of Tc group (t=15.954,P＜0.05).Conclusion Tracer-based MRI can be used to investigate the rule of transportation in ECS,and the transportation and clearance of substances into the ECS can be influenced by a selective external stimulation.

Objective:To investigate the relationship between single nucleotide polymorphic (SNP) loci of PLCE1 gene and primary nephrotic syndrome (PNS) and its response to glucocorticoid therapy in Guangxi Zhuang children. Methods:It was a retrospective cohort study. One hundred and fifty-five Guangxi Zhuang children with PNS in the Affiliated Hospital of Youjiang Ethnic Medical College from October 2020 to May 2022, and 100 healthy Zhuang children during the same period as controls were included. Four SNP loci including rs17109674, rs10786156, rs3740360 and rs2274224 of PLCE1 gene were selected and high-throughput sequencing was used to analyze the genotypes. Logistic regression analysis model was used to analyze the correlation between each SNP locus and onset of PNS and steroid-resistant nephrotic syndrome. The SHEsis online software was used to analyze the link disequilibrium of each SNP locus, and construct the haploid type. Results:(1) Logistic regression analysis results showed that AC+CC genotype (AA as reference, OR=0.449, 95% CI 0.256-0.786, P=0.005), AC genotype (AA as reference, OR=0.354, 95% CI 0.188-0.667, P=0.001) and C allele gene (A as reference, OR=0.615, 95% CI 0.390-0.971, P=0.037) of rs3740360 were correlated with the risk of PNS in children. The genotypes and allele genes of rs17109674, rs10786156, rs3740360 and rs2274224 were not associated with the risk of steroid-resistant nephrotic syndrome in children (all P>0.05). (2) Strong linkage disequilibrium existed between rs10786156 and rs2274224 ( D'=0.702, r2=0.484). rs17109674 and rs10786156 ( D'=0.128, r2=0.007), rs17109674 and rs3740360 ( D'=0.142, r2=0.007), rs17109674 and rs2274224 ( D'=0.045, r2=0.001), rs10786156 and rs3740360 ( D'=0.255, r2=0.023), and rs3740360 and rs2274224 ( D'=0.281, r2=0.028) all had weak linkage disequilibrium. (3) The haploid AGCG ( OR=0.282, 95% CI 0.079-1.008, P=0.038), GGCC ( OR=0.327, 95% CI 0.111-0.967, P=0.034) and GGAG ( OR=4.616, 95% CI 1.179-18.069, P=0.016) were all correlated with the risk of PNS in children. Conclusions:AC genotype, AC+CC genotype, and C allele gene of rs3740360 SNP locus may reduce the risk of PNS in Guangxi Zhuang children. Haploid AGCG and GGCC may be associated with decreased incidence of PNS, while GGAG may be associated with increased incidence of PNS in Guangxi Zhuang children. The genotypes and alleles of 4 SNP loci are not associated with the risk of steroid-resistant nephrotic syndrome.