Objective:To investigate the changes in structural brain network topology and microstructural damage in patients with multiple sclerosis (MS), and to analyze its correlation with cognitive function.Methods:Clinical and imaging data of 114 patients with MS (MS group) diagnosed in the First Affiliated Hospital of Chongqing Medical University from May 2021 to September 2022 were analyzed retrospectively. In addition, 71 volunteers were recruited as a healthy control group (HC group) during the same period. All subjects were performed on cognitive assessment and 3D-T 1 magnetization-prepared rapid gradient echo, 3D-fluid-attenuated inversion recovery, and diffusion kurtosis imaging (DKI) scans. GRETNA software was used to obtain network topology attributes, and global attributes included global efficiency, local efficiency, and small-world attributes [clustering coefficient(Cp), shortest path length(Lp), normalized Cp(γ), normalized Lp, and small-world index (σ)]. Local attributes included betweenness centrality (BC), degree centrality (DC), nodal clustering coefficient (NCp), nodal efficiency, nodal local efficiency (NLe) and nodal shortest path length. The DKI parameter map generated by the post-processing software was used to extract the DKI parameter values of the brain region with abnormal local topology of the brain structure network. The differences of global attributes, local attributes and DKI parameter values [kurtosis fractional anisotropy (KFA), mean kurtosis (MK), radial kurtosis (RK) and axial kurtosis (AK) values] were analyzed by independent sample t-test or Mann-Whitney U test, and corrected by false discovery rate (FDR). Spearman or Pearson correlation analysis was used to evaluate the correlation between abnormal brain structure network topology attributes and cognitive scale scores in the MS group. Results:Both the MS group and the HC group structure network showed small-world attributes, and the γ and σ values of the MS group were significantly lower than those in the HC group (FDR correction, P<0.05). Compared with the HC group, BC, DC, NCp and NLe broadly reduced in the MS group, mainly involving in bilateral frontal, temporal, precuneus, amygdala, and thalamus (FDR correction, P<0.05). After FDR correction, compared with the HC group, the KFA, MK, RK and AK values of 23 brain regions with abnormal local attributes of the network in the MS group were significantly changed in several brain regions (FDR correction, P<0.05). The correlation analysis showed, after FDR correction, the DC value of the right putamen in MS patients was positively correlated with the digit span test (DST) scores ( r=0.318 ,P=0.001). Conclusion:There are extensive changes in the structural brain network of MS patients, accompanied by varying degrees of microstructural damage, and the reduction of degree centrality in the basal ganglia putamen region is associated with cognitive impairment.

ObjectiveThe effect of inoculation with different organophosphate-resolving bacteria or compound bacteria on the quality of Paris polyphylla var. yunnanensis medicinal materials and rhizosphere soil fertility were studied to provide a reference for the development and application of biological bacterial fertilizer in artificial cultivation of P. polyphylla var. yunnanensis. MethodThe three dominant species of organophosphate-solubilizing bacteria were inoculated separately and in combination in sterilized soil by single-factor indoor pot planting， and no inoculation was used as the control group. The effect of inoculation of organophosphate-solubilizing bacteria on total saponins content in rhizomes of P. polyphylla var. yunnanensis， as well as microbial numbers， enzyme activities and nutrient contents in rhizosphere soil were analyzed. ResultIn the seven treatments inoculated with organophosphate-solubilizing bacteria， the total saponin content in the rhizomes of Paris polyphylla var. yunnanensis was increased by 16.42%， 3.83%， 16.86%， 33.69%， 2.11%， 13.44%， and 28.83%， respectively， compared with the control. Inoculation with organophosphate-solubilizing bacteria increased the number of soil microorganisms to varying degrees， and the effects of S6 and S7 treatments were the most significant. Inoculation with organophosphate-solubilizing bacteria improved the enzyme activity， and the effect of S7 treatment was the most significant. The activities of acid phosphatase， neutral phosphatase， alkaline phosphatase， protease， invertase and catalase were 49.96% and 104.67% ， 110.17%， 99.61%， 26.26%， 11.29% higher than those of the control， respectively. Inoculation with organophosphate-solubilizing bacteria reduced the pH of the rhizosphere soil and increased the content of soil available nutrients. Under the S7 treatment， the contents of alkaline hydrolyzable nitrogen， available phosphorus and available potassium in the rhizosphere soil of P. polyphylla var. yunnanensis were 181.46%， 51.64% and 42.62% higher than those of the control， respectively. Correlation analysis showed that there was a significant positive correlation between total saponins and phosphatase activities， a significant positive correlation between soil microorganisms and soil enzyme activities， and a very significant positive correlation between soil nutrients. ConclusionInoculation of different organophosphate-resolving bacteria or compound bacteria can improve the quality and rhizosphere soil fertility of P. polyphylla var. yunnanensis. Among them， the mixed inoculation of three kinds of bacteria and the mixed inoculation of B. mycoides and B. wiedmannii have the best effect.