Lymphoid structure in repair of spinal cord acupuncture injury / 中国实验动物学报

ABSTRACT

Objective To observe the distribution and characteristics of lymphatic vessels in normal and injured mouse spinal cord,and to determine if lymphatic vessels participate in the repair of spinal cord injury.Methods Thirty-nine adult male KM mice were divided randomly into a normal group(n=6)and an injured group(n=33).Mice in the injured group were further divided randomly into mice examined on postoperative days 1,3,5,7,and 14.Three mice in the injury group died after acupuncture injury,and the sample was subsequently supplemented randomly.Spinal cord damage was induced in the injured group by acupuncture,while mice in the normal group had no spinal cord damage.The distribution of lymphatic endothelial cells(LECs)in the spinal cord was detected by immunohistochemistry,and expression levels of the lymphatic endothelial cell markers prospero-related homobox-1(prox-1),lymphatic vessel endothelial cell hyaluronic acid receptor-1(lyve-1),and flat foot protein(podoplanin),and the vascular endothelial cell marker CD34 were observed in the spinal cords in normal and acupuncture-injured mice.Spinal cord samples were examined by immunofluorescence staining,and the source of new LECs was explored by observing the co-expression of lyve-1/prox-1,lyve-1/podoplanin,and CD34/prox-1.Results Lymphangioid structures were present in the spinal cord in normal mice and were distributed in segments,laterally between the white matter and gray matter.Nascent lymphangioid-like structures appeared in the spinal cord at the site of acupuncture injury,and prox-1,podoplanin,lyve-1,and CD34 were expressed simultaneously;however,these nascent lymphangioid-like structures disappeared after scarring during spinal cord injury.Conclusions Segmental,transversely distributed lymphangioid-like structures are present in the spinal cord in normal adult mice,and neonatal lymphangioid-like structures are involved in the reconstruction of spinal cord injury.These nascent LECs may originate from the surrounding existing lymphatic vessels or from vascular endothelial cells.