Immunohistochemical Analysis Of The Spatial Distribution Of Nerves And Lymphatics Around The Inferior Mesenteric Artery

ObjectiveImmunohistochemical analysis was used to study the spatial distribution of nerves and lymphatic vessels around the inferior mesenteric artery,which provided a morphological basis for the treatment of inferior mesenteric artery and left colon artery in radical resection of rectal cancer,and to discuss the standard procedures of vascular treatment in radical resection of rectal cancer through review the related literature.MethodsThe study was performed on 13 cases of postoperative specimens of rectal cancer and fixation with 10% formalin solution(all specimens underwent high ligation of the inferior mesenteric artery).From the beginning of the main trunk of the inferior mesenteric artery to the beginning of the left colon artery,Obtaining the inferior mesenteric artery and its surrounding tissues which is perpendicular to the inferior mesenteric artery(4 specimens were taken from the inferior mesenteric artery to inferior mesenteric vein and its surrounding tissues),the tissue was continuously cross-sectioned after dehydration and paraffin embedding(each slice was 4 um thick and cut continuously for four pieces).Hematoxylin-eosin(HE)staining and immunohistochemical staining of vascular endothelial cells(anti-CD34)?nerve fibers(S-100)and lymphoid endothelial cells(D2-40 antibody)were performed on the sections of specimen respectively.The spatial distribution of nerve fibers and lymphatic vessels in the tissue around the inferior mesenteric artery was observed and recorded under the microscope.Results1.The IMA sheath is mainly composed of circular-distributed dense connective tissue,the inner boundary of which is the outer edge of the annular smooth muscle layer,and the lateral border is the medial margin of loose connective tissue,the average thickness is about 550um;2.Lymphatic vessels can be seen in the sheath of the inferior mesenteric artery,which is evenly distributed around the inferior mesenteric artery,while the lymphatic vessels in the loose connective tissue of the IMA sheath are scattered and have no directional distribution difference;3.The distribution of nerves in the inferior mesenteric artery sheath is sparse,and most of the nerve bundles are located in the loose connective tissue outside the vascular sheath;4.In terms of spatial distribution,close to the inferior mesenteric artery,the nerve distribution is relatively dense,mainly distributed to the left of the inferior mesenteric artery and between the inferior mesenteric vein.The closer to the inferior mesenteric vein,the less the nerve is distributed.Compared with the nerve,the lymphatic vessels are distributed in the IMA sheath and loose connective tissue of the IMA sheath,Only a few nerves intersect with lymphatics to some extent in the arterial sheath.Conclusions1.There is a distribution of lymphatic vessels in the sheath and extrathecal sheath of the inferior mesenteric artery.If lymph nodes of IMA root need to be dissected,the sheath of inferior mesenteric artery needs to be removed.The physiological function of lymphatic vessels in arterial sheath needs further study.2.The autonomic nerve fibers are mainly distributed outside the inferior mesenteric artery sheath.Skeletonization of the inferior mesenteric artery must removed the inferior mesenteric artery sheath and the surrounding autonomic nerves at the same time.Choroidization of the inferior mesenteric artery,leaving loose connective tissue around it,which may preserve the vegetative nerves distributed to the left colon.3.In the tissues from the root of inferior mesenteric artery to the beginning of left colonic artery,the autonomic nerve fibers emitted from the inferior mesenteric plexus mainly distributed on both sides of the inferior mesenteric artery and the left side is denser than the right side,then distribute to the left colon.