I study development of mesenteric lymph nodes (MLN) in white rat, including 40 embryos of 12-21 days, the 10 new-born΄s (first day) and 40 rats of first month, on serial histological sections, staining by hematoxylin and eosin, picrofuxine, azur-II and eosin, silver nitrate with graphice reconstruction, and total preparations after injection of dark-blue mass of Gerota into mesenteric lymphatic bed. In the fetuses of 18-19 days cranial mesenteric artery and its branches invaginate into lumen of neighbouring mesenteric lymphatic vessels together with their endothelial walls and intermediate connective tissue. In result is formed common anlage of MLN as stromal tape. It becomes lymphoid tape in the fetus of 20 day. The tape narrows and loosens (decreasing of quantity of lymphocyties) in distal direct. In ventral direct from head of pancreas the lymphoid tape is discovered only in lumen of left mesenteric lymphatic trunk. Right mesenteric lymphatic trunk remains before head of pancreas by means of screening of wide cranial mesenteric vein. In the fetuses of 20-21 days this lymphoid tape is deformed (on sections it has crimped shape or consists of fragments with different sizes and shape) under pressure of neighbouring organs or in result twisting of root of mesentery. In the fetus of 21 day and new-born rat the tape is divided on the separate MLN with oval, round and bean΄s shape in connection with thickening of their capsules and accumulation of lymphocyties in their parenchyma. I didn΄t find MLN with tape form, but saw solid chain of paracolic MLN before head of pancreas. The central and possibly peripheral MLN lie along and about mesenteric lymphatic trunk, but MLN never interrupt it.
The work was submitted to international scientific conference «Fundamental and applied research in medicine», France (Paris), 15-22 October 2011, came to the editorial office on 05.09.2011.