An experimental study of artificial murine bladder reflex arc established by abdominal reflex / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The neurogenic bladder dysfunction caused by spinal cord injury is difficult to treat clinically. The aim of this research was to establish an artificial bladder reflex arc in rats through abdominal reflex pathway above the level of spinal cord injury, reinnervate the neurogenic bladder and restore bladder micturition.</p><p><b>METHODS</b>The outcome was achieved by intradural microanastomosis of the right T13 ventral root to S2 ventral root with autogenous nerve grafting, leaving the right T13 dorsal root intact. Long-term function of the reflex arc was assessed from nerve electrophysiological data and intravesical pressure tests during 8 months postoperation. Horseradish peroxidase (HRP) tracing was performed to observe the effectiveness of the artificial reflex.</p><p><b>RESULTS</b>Single stimulus (3 mA, 0.3 ms pulses, 20 Hz, 5-second duration) on the right T13 dorsal root resulted in evoked action potentials, raised intravesical pressures and bladder smooth muscle, compound action potential recorded from the right vesical plexus before and after the spinal cord transaction injury between L5 and S4 segmental in 12 Sprague-Dawley rats. There were HRP labelled cells in T13 ventral horn on the experimental side and in the intermediolateral nucleus on both sides of the L6-S4 segments after HRP injection. There was no HRP labelled cell in T13 ventral horn on the control side.</p><p><b>CONCLUSION</b>Using the surviving somatic reflex above the level of spinal cord injury to reconstruct the bladder autonomous reflex arc by intradural microanastomosis of ventral root with a segment of autologous nerve grafting is practical in rats and may have clinical applications for humans.</p>

Monolayer culture followed by three-dimensional culture of chondrocytes: A two-step method / 第二军医大学学报

Objective: To explore an ideal method for culturing autologous chondrocytes while maintaining their cartilaginous phenotype by combining monolayer culture with three-dimensional culture. Methods: Chondrocytes were cultured by routine monolayer culture method, then the chondrocytes of fourth passage were seeded into alginate beads for three-dimensional culture following standard protocols. The cell morphology was observed by inverted microscope at predefined time points. The cell viability and proliferation were tested by trypan blue and LIVE/DEAD® Kit, respectively. And extracellular matrix formation was examined by toluidine blue staining. Results: The cartilaginous phenotype of chondrocytes could only be maintained by passage 2 and 3 after monolayer culture. Three-dimensional culture could gradually regain and maintain the cartilaginous phenotype of de-differentiated chondrocytes (P4). Cells of P1-3 by monolayer culture could maintain 90% activity, which decreased from P4. The cytoactivity of cells by three-dimensional culture method was always above 90%. The total doubling rate till P6 by monolayer culture (28 days) was 44 times that by three-dimensional culture. The staining intensity of cartilaginous extracellular matrix was significantly decreased after P4 by monolayer culture (P<0.05). For three-dimensional method, the staining intensities of cartilaginous extracellular matrix at day 21 and 28 were significantly higher than that at day 7 (P<0.05). Conclusion: Monolayer culture allows proper proliferation of chondrocytes, and following three-dimensional culture in alginate beads can regain the cartilaginous phenotype of chondrocytes, thus achieving the aim of both amplification and maintenance of the cartilaginous phenotype.