To study the ultrastructural pathological characteristics of vascular and connective tissues in primary syphilis. The histomorphological changes in the dermis were examined with transmission electron microscopy. Capillaries with a thickened multilayered basement membrane,occluded lumen, and proliferation of endothelial cells were found. The spirochetes entered the capillary vessel through the basal membrane and endothelial cells, and were separated or attached to red blood cells.Large numbers of inflammatory cells were found around the blood vessels.There were T.pallidum in the cytoplasm.The pathological changes in the capillaryies and connective tissue were morphological basis for the study of pathogenetic mechanism of primary syphilis.

Objective:To investigate the effect of treadmill training on spasticity and the expression of potassium chloride co-transporter 2 (KCC2) after blocking BDNF-TrkB signaling pathway in rats with incomplete spinal cord injury (SCI).Methods:Forty female Sprague-Dawley rats were randomly divided into a sham-operation group (Sham group), an SCI+ phosphate-buffered saline group (SCI/PBS group), an SCI-treadmill training+ PBS group (SCI-TT/PBS group), an SCI/TrkB-IgG group and an SCI-TT/TrkB-IgG group. All of the rats underwent 1 week of intrathecal catheterization, and then T 10 incomplete SCI was induced. In the Sham group the spinal cord was only exposed. Seven days later, BDNF-TrkB signaling was blocked in the SCI/TrkB-IgG and SCI-TT/TrkB-IgG groups using the TrkB-IgG. The remaining three groups were controls treated with PBS. The SCI-TT/PBS and SCI-TT/TrkB-IgG groups began exercising 7 days after the SCI and continued for 4 weeks. The spasticity in their hind limbs was assessed using the Asworth assessment and H reflex (H-max/M-max ratio). The expression of KCC2 in the distal spinal cord was detected using western blotting and immunohistochemistry. Results:After the SCI the average Ashworth spasticity grades of the four SCI groups increased significantly compared with the Sham group. The average Ashworth spasticity grade of the SCI-TT/PBS group was significantly lower than those of the SCI/PBS and SCI/TrkB-IgG groups in the 3rd through the 5th week, and the SCI-TT/PBS group′s average grade was significantly less than that of the SCI-TT/TrkB-IgG group after 4 weeks. Within 5 weeks the average H-max/M-max ratio of the Sham group remained unchanged, significantly lower than the other 4 groups′ averages. There was no significant difference in the H-max/M-max ratio among the 4 groups of injured rats within 2 weeks after the SCI, but after 3-5 weeks the average H-max/M-max ratio of the SCI-TT/PBS group was significantly lower than those of the SCI/PBS, SCI/TrkB-IgG and SCI-TT/TrkB-IgG groups. At the 4th and 5th week the average H-max/M-max ratio in the SCI-TT/TrkB-IgG group was significantly lower than that in the SCITrkB-IgG group. And after 5 weeks the average expression of KCC2 in the anterior horn of the injured spinal cord was significantly lower in the 4 SCI groups than in the Sham group. Exercise significantly increased the expression of KCC2 in the SCI-TT/PBS group, and its immune intensity and relative optical density were significantly higher than those in the SCI/PBS, SCI/TrkB-IgG and SCI-TT/TrkB-IgG groups. However, there was no significant difference between the SCI/TrkB-IgG group and the SCI-TT/TrkB-IgG group.Conclusions:Treadmill training can improve spasticity after incomplete SCI and the expression of KCC2 in the distal spinal cord, at least in rats.