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DOI: http://dx.doi.org/10.20534/ESR-17-5.6-36-41
Sadriddinov Asomidin Fayazovich, Tashkent Pediatric Medical Institute, MD, head department of histology Abdullaeva Nigora Erkinovna, student of Tashkent Pediatric Medical Institute Sadriddinova Muborakhon Asomidinovna, student of Tashkent Pediatric Medical Institute Fakhriev Jahongir Alisherovich, student of Tashkent Pediatric Medical Institute
Shoyunusov Sarvar Ikromovich, student of Tashkent Pediatric Medical Institute E-mail: asom-sad-23@mail.ru
THE CLASSIC HEPATIC LOBULE IS IN THREE DIMENSIONS: ORGANIZATION, CYTOACRCHITECTURE AND HEMOCIRCULATORY MAINSTREAM OF SIMPLE HEPATIC LOBULE FOR RAT AND HUMAN
Abstract: It was determined, that simple classic hepatic lobule has polyedric shape, on it's lateral surface the inter lobular vein passes, that gives short branches inside lobule, being branched into 2-3 sinusoid hemocapillaries, those fan-shapely or radially direct to central vein, being revealed only in middle part of lobule. The blood outflow is carried out through intercalary vein, being connected out of the lobule with sublobular vein.
The aim of study. Clarification peculiarities of microcirculatory bed for hepatic lobule at biliary obstruction and recanaliza-tion of bile.
Material and methods. Experimental model of mechanical jaundice (white rats n = 54) was reprotucted in 3 series. The restoration processes were observed in thelOth, 20th and 25th days of cholestasis in the terms of 5,15 and 30,90 days after secondary operation. The parts of hepatic tissue, and, also, histological preparations with filling vessels were processed by general morphological methods of study.
Results: At development of restorative processes after cholestasis in 20 days it was clearly separated classic hepatic lobule. It was determined the ordinary hepatic lobule has polyedric shape, the interlobular vein passes on it's lateral surface, from that the short branches inside of lobule, and, they are, at once, fall to sinusoid capillaries. Sinusoid hemocapillaries have fan shaped direction in upper part of lobule, in middle and lower third part they are radial, being flow into central vein. The central vein is revealed in the middle third of lobule, then it, bending, goes out from the lobule and connects wit sublobular vein
Keywords: classic hepatic lobule, hemocirculatory bed, interconnection of interlobular vein, sinusoids and central vein.
Introduction recanalization of experimental cholestasis in different periods, were
Last years the considerable progress was reached in study struc- summarized.
tural organization ofliver, it's components construction peculiarities Materials and methods.
were specified. Together with classic hexagonal hepatic lobule in the Experimental model of mechanical jaundice was reproduced on
liver the simple and complicated complexes, acinar and portal lobules 54 rats weighting from 140 to 160 by ligation of general bile duct
such as structural and functional units of organ [2; 5; 6; 7; 8; 11].In and its transection between two ligatures.To monitor the dynam-
hemocirculatory mainstream ofliver the systems of inflow, circulation ics of morphological changes for the rats (n-24) with bile ducts,
and outflow are also separated. But, so far, the notions on architecture they were killed interims of 5,10,20 and 30 days of cholestasis. The
hemocirculatory mainstream of classic hepatic lobule for man, rat and remaining (n-30) were restored the bile flow after 10 and 20 days
some other mammals are not concretized. In general they are based of cholestasis. At these terms the duct stump was large and had
on summarization a wide variety of opinions on hepatic lobule, or, transparent bile. Choledochoduodenoanastomosis was created
they are made up on computer graphics, that is caused to a certain with attaching the enlarged duct to duodenum's wall. To restore the
extent, due to the complexity of its perfect identify. biliary outflow to the intestine the puncture of bile duct through
Obviously, in this regard, there is no clear understanding on the duodenal wall was performed, and, the place of puncture on
characteristics of transition interlobular, vessels to interlobular, on external wall of duodenum was sutured with a traumatic needs. The
topography of central vein with sublobular vein. bile outfow restoration in intestines was monitored by the general
In connection with it, the results of study cytoarchitecture condition of animals icteric staining of urine and bilirubin level in
and hemocirculatory mainstream of classic hepatic lobule during blood serum.
The dynamics of recovery process was controlled with two series of experiments in terms from 15 to 30 days after choledocho-duodenoastomosis application.
The hepatic tissue parts from cycle and experimental animals were fixed in Carnya, OFS mixture, and, they were covered with paraffin, the sections were colored by Mallory, Gomory with hematox-ylin-eosine. The microcirculatory mainstream was researched with drugs after filling in the hepatic vessels with Gerot Akilov's mass [4].
Results of study. The morphological researches determined that deformity of hepatic lobule was already worked at 10th day of cholestasis, when multiple proliferating bile ducts, sometimes being wedged in lobule's, at lobule's periphery. But the structure of hepatic plates, topography of central vein have no essential changes. While progressing mechanical jaundice (20 days) the proliferating bile ducts are wedged in lobules, fragmenting them into separate parts. In connection with it hemocirculatory mainstream of lobule is reconstructed, and, at the result the central veins are replaced to the periphery, and, the lobules disappear. Therefore, at this stage of reconstruction the hepatic lobules are represented as deeply dissected growing bile ducts and connective tissue.
Study liver structure after recanalization of 10 daily cholesta-sis, showed full recovery of livers architecture by the 15th day of postoperative period. The reversibility of pathological processes at cholestasis with duration 20 days occur more slowly, and it is connected with preservation fibrotic tissue in interlobular parts of liver
parenchyma. The connective tissue elements disappear in the lobules firstly, they become gradually thinner, and, they are partially absorbed at interlobular areas. On the 15 th day at 20 daily cholestasis the interlobular structures are fully restored, the hepatic plates are oriented radially, the lumen of sinusoids is moderately enlarged and contains a few elements of blood. But at that period duct to presentation of fibrous septa in interlobular areas the classic hepatic lobule is clearly detached and contoured that creates ideal conditions for it's study. Thanks that on preparation being colored by Mallory or at filling vessels the transverse, oblique ort longitudinal lobule's section is easily distinguished. On these preparations the lobules are limited with thin stripe of sclerotic tissue or avascular areas, surrounding them from all sides. In connection with it the main morph functional analysis of hepatic lobule was performed on the material of 20 daily cholestasis. Except fibrous layers with additional criteria of identification for hepatic lobules their volume, trias localization sinusoidal orientation, topography of central vein, thanks that the plane of section is easily determined.
On transverse section the hepatic lobule has expressed penta-or hexagonal shape, it's angels, because of portal structures (artery, vein, bile duct and lymphatic vessel) are slightly rounded and there is central vein in the center of lobule, where the hepatic plates and sinusoidal capillaries are converged. The level of section is determined by the volume and diameter of central vein (pict. 1a).The narrow lumen of central vein indicates the initial portion of the lobule.
Picture 1.Cytoarchitectonics and hemocirculatory bed of classic hepatic lobule; A is transverse section of upper lobular part: the pentagonal shape of lobule. Staining by Mallory ob. 10. st. 10; B is transverse section of lobular middle third. Filling in vessels with Paris blue. Incr. Vol. 10, stain. 10
Designation here and there:
- sv — sublobular vein, fn - fibrous net, s - sinusoid, iv - interlobular vein, cv - central vein, int v - intercalary vein, bd - biliary ducts, ia - interlobular artery, bc- bile;
- canaliculy, sv - septal vein.
At picture 1b (middle level of section) after filling vessels in lobule the multiple radially directed sinusoids, connecting with central vein, are seen. In the corners of lobule the interlobular veins with contrast content, giving short vessels (according to septal branches)
are revealed the side of interlobular capillaries. At oblique section the lobule is characterized with conical shape and clear bordered wide flat fibrous tissue, and, in center oflobule the narrow section of central vein are revealed, and, in lover part of lobule it is clearly passed in transverse cutting inserting vein with round contours. In pictures 1c and 1d the cytoarchitecture and hemocirculatory mainstream of hepatic lobule are observed, they are full of contrast substance, and, they are revealed in the area oflobule's angles. More over in the upper part ofthe lobule the sinusoid capillaries have fan-shaped location, and, in middle
and lower parts they are radial. At successful parallel incision of interlobular and central vein it is clearly seen their interconnection. As it is
seen on picture 3 the interlobular vein is on lateral surface of two closely located lobules, from that the short processes are branched.
Picture 2.Interconnection of sinusoid capillaries, central vein and insert vein in lobule. A - is longitudinal section of hepatic lobule.In upper lobular part the sinusoid are orientated fan-shaped, in other part they are radially, and, all they flow in central vein, in low lobular third it passes to insert vein. Filling in vessels with Paris blue. Vol. 10. St. 10; B - is oblique section of lobule. Topography of lobular cytoarchitectonics and hepatic plates according to central vein. The part of going out insert vein from lobule and its connection with sublobular vein. Staining by Mallory, Vol. 10. St. 10
These subsequently located short processes at once are divided into 2-3 identical by the diameter sinusoid hemocapillaries. Inside lobule the sinusoid capillaries interlacing with each other ruch on the side of central vein and join it. It should be marked that at the same picture the central vein, not reaching the lower lobule's border, bends it, and, goes out from it, the fragment of this vessel, and, it is found out on the lobule's periphery. It is important to underline that in literature there is absent clear imaginations on interrelations of sinusoid capillaries with central vein in different parts of lobules,
and, also peculiarities of crossing parts for central vein to sublobular vein. In connection with it we analyzed serial incisions ofhepatic lobules, after filling vessels beginning from upper boundary surface and finishing the lower one. In given study, except the above mentioned lobule's orientations, we took into account the appearance longitudinal incision of central vein to it's crossing to fixed vein, being connected with sublobular vein. Construction of part serial incisions, including longitudinal section, central vein and it's connection with sublobular vein are presented on picture 4.
Picture 3. Hemocirculatory bed and
At very surface incision, bouldering with the above laying lobule, the sinusoids located without order, and, on periphery the lobules in some parts occur being filled with contrast substance the interlobular veins from those inside the short processes are branched. On the next sections the sinusoids acquire radial orientation, the oblique cut lower and upper fragments of central vein, locating in
cytoarchitectonics of hepatic lobule
accordingly parts of lobules (pic 4 b), occur. In upper thirds of lobules the fan-shaped location of sinusoid capillaries in relation to central vein, are marked. In difference from interlobular veins the lumen of central vein is empty, and, in beginning part it has the least diameter. By the measure of approaching to lower part of lobule the lumen of central vein is gradually enlarged. Therefore, the clearly
making out lumen of central vein appear not on the apex, but at the level of middle third part of the lobule.Just at this space here only radial directing sinusoid capillaries flow in. Further the central vein no reaching the lower part of lobule perimeter, curves and directs to the side of interlobular tissue (pic 4d). In this space, including the part of flexion, many sinusoid capillaries, locating both laterally and lower from it (pic. 4 e) entering the central vein passes to insert vein, that curving is directed transversely to periphery of the lobule, is connected with sublobular vein. (pic. 4 f). Moreover, on the last picture it is well differed vein of longitudinal section for central vein
of neighbor lobule, where the sinusoid capillaries are orientated, that are also coming from the interlobular vein. At the lowest sections the orientation of hemocapillaries again disorder, the lobule decreases in volume and gradually passes the next lobule.
On the 30th day of restoration after 20th day of cholestasis the interlobular connective tissue becomes considerably thin, and, only in separate parts of parenchyma the fibrous septa are saved, and, in the others the interlobular connective tissue fully disappeared, because of that the lobular borders are flowed in. Such picture is followed on preparations with vessel's filling.
Picture 4. Construction of serial sections longitudinal section of hepatic lobule. Vol. 7. st. 10. Filling in vessels with Paris'blue.Explanation is in text
At liver's examination of patients with gallstone diseases, being complicated with obturational jaundice, we determined, that in some cases the hepatic lobule was contoured well, though fibrous septa are not developed well (pic. 5 a, b).Comparative study cytoar-chitectonics of human hepatic lobule show, that it has the same volume and prolonged shape, and, it is a little differ from the lobule of experimental animals.In picture 2 c the oblique longitudinal section of hepatic human lobule, where the liver plates and sinusoids are located in disorder, obviously, the section was not passed on central vein's level. On another oblique longitudinal section of lobule (pic. 2 g) the lobule has cone-shaped with eccentric dislocation of
large vessel obviously mathing to insert vein, having the same passage as experienced animals.
Our morphometric studies showed, that, like prism, the hepatic lobule has several dimensions. On transverse section the diameter of lobule is 0,65 ± 0,03 mm, the lest one is 0,4 ± 0,01.On the longitudinal section the length of lobule is 1,1 ± 0,1 mm the width is 0,45 ± 0,02 mm.Contours of pentagonal lobule are more clearly divided at staining by Gomory. On the 30 th day after restore the flow out of bile, only in interlobular parts the argyrofile frame stays thickened and hyperplased especially around bile ducts, where the fibers form small looped net. Inside lobules the reticulin fibers braid hepatic plates,
being located on the way of sinusoid liver capillaries. From the one side they are connected with wall of central vein from the other side
with argyrofile frame of portal tracts, thus forming united integral frame of hepatic lobule.
Picture 5. Interconnection of sinusoid capillaries, central vein and insert vein in lobule
A is liver of patient with gall-stone disease, being complicated with obturational jaundice. The contours of hepatic lobule (longitudinal section, there is central vein in lower part)are well marked out. Staining with hematoxilineosin. Vol.10St.10 B is the same case, oblique section of lobular lower part. Excentrically located insert vein. The same staining. Vol. 10 St. 10.
Directing in transverse and vertical planes, they do not only keep hepatic planes in strict definite position, but also prevent from constriction or collapsed walls of blood capillaries, and, by that, it provides free blood flow in sinusoids, promoting favourable exchange between blood and hepatic cells.
Discussion
The results of taken researches show, that in early terms of cholestasis, when per lobular fibrosis is developed in liver, after recanali-zation, by 15 days the branched interlobular connective tissue is fully disappeared, and, also the parenchymatous elements are restored. In the cases of long cholestasis (20 days) in connection with considerable disorganization both stromal and parenchymatous elements, restoration processes are considerably become slow, and, they are depend on changes level ofhemocirculatory source, especially central vein. In cases of keeping central vein, though eccentrically, the cytoarchitec-tonics ofhepatic plates and sinusoid capillaries, the interlobular fibrous septa are still kept long, due to that, the hepatic lobule is well shaped.
Picture 6.Simplified scheme of structural organization cytoarchitectonics and hemocirculatory bed of simple classic hepatic lobule
Our taken data on quantitative parameters of topography vascular system, morphology transverse and longitudinal sections allow to consider that hepatic lobule has the kind of many-sided prism, being enlarged in its low part. The diameter of this prism is from 0,36 to 0,4 mm, and, from 0,5 to 0,6 mm accordingly, on the apex and base, the length is from 1,0 to 1,1 mm. The comparative study volume, shape, cytoarchitectonics and hemocirculatory source, and, also parameters of classic hepatic lobule of rat and man were the same, and, they were coincided with the data of other researches [1; 3; 9].
At analysis of serial sections of liver it was determined that central vein is clearly revealed only in its middle third, and, then it is going down, and, not approaching to lower border, bending, passes into insert vein. The last is connected with sublobular vein, being located out of hepatic lobule. On the base of morphometric and demonstrative photos on cytoarchitechtonics and hemocirculatory source of lobule we work out the scheme, reflecting topography of its structural elements.The given scheme of longitudinal section for classic hepatic lobule is the most fully reflected not only it's shape, volume, buff and localization of original interconnections of hemocirculatory (pict. 5).Thus, the established spatial model of classic hepatic lobule, apparently, the most exactly correspond to true ar-
chitectonics oh hepatic lobule in situ. Moreover many parameters of hepatic lobule of rat were close the same at human.
Conclusions.
1. The classic hepatic lobule of rat and human by shape, volume, cytoarchitectonics and hemocirculatory bed occur the same, and, in transverse section it has pentagonal shape, and, in longitudinal section it reminds polyhedral prism, and there axially passes the central vein, has pentagonal prism, and, there axially passes the central vein, where the sinusoid hemocapillaries converge.
2. Morphological studies of hemocirculatory bed of hepatic lobule show, that interlobular vein is located on its lateral surface and participated in formation the triad of liver together with biliary duct and arteries. From interlobular vein successively branch off the short processes, apparently, in accordance with septal veins those are just branched into 2-3 sinusoid hemocapillaries.
3. Sinusoid hemocapillaries in upper part oflobule topographically have fan-shaped, in middle and lower third the radial directions, and, in the center the lobules are flown in central vein.
4. In classic hepatic lobule the central vein topographically is revealed only in its middle third on the level of low third, deviating passes to insert vein, and, it is connected with sublobular vein
1.
2.
3.
4.
5.
6. 7.
9.
10. 11.
12.
at interlobular parts. References:
Bahadirov F.N, Alimjanov F.N, Sheverdin V. A. Complex construction of microcirculatory bed of liver postnatal ontogenesis after liver's resection and at experimental toxic damage. "Morphology". - Uzbekistan. - 1998, 3:23.
Bluger A. F. Structure and function of liver at epidemical hepatitis. - Riga; publ. A. H. Latv. SSR, - 1964. - P. 3 90. Kapustina E. B. Construction of complexes hepatic lobules in liver of human and cat. "Archives of anatomy, histology and embryology" - 1973. - V. 65, - w 12, - P. 37-41.
Maligin A. I. New method of clarification anatomic preparations. "Azerbaydjan. med. journal", - 1959, - w 6, - P. 75-81. Hruschov G. K., Brodsky V. Y. Organ and cell (some problems of cytology and histology).Progress in modern biology. - 1961, - V. 52, - w 2. - P. 181-207.
Arias I., WolkoffA., Boyer J., Shafritz D., Fausto N., Alter H., Cohen D., Eds. The Liver: Biology and Pathobiology. Wiley, - 2010, -1216 p.
Ekataksin Wichai Wake Kenjiro. Liver units in tissue skeleton in porcine liver with particular reference to the "compound hepatic lobuli". Amer. J. Anat. - 1991. - 191, - No. 2 - P. 113151.
Kuntz E., Kuntz H.D. Hepatology. Principles and Practice: History, Morphology, Biochemistry, Diagnostics, Clinic, Therapy. Springer; 2th ed, - 2005, - 906 p.
Maddrey W. C., Feldman M., Eds. Atlas of the Liver =. 3 rd ed., Current Medicine Group, - 2003, - 336 p. McNally P. GI / Liver Secrets. 3rd ed., Mosby, - 2005, - 800 p.
Rapport A. Acinar units and the pathophysiology of the liver // Jn: The Liver, Morphology, Biochemistry, Physiology (Ed. c.Rouiller) Acad.Press., - New York, - 1965. - V. 1. - P. 265-328.
Schiff E. R., Sorrell M. F., Maddrey W. C., Eds. Schiffs Diseases of the Liver. - 2 vol. set, - 10th ed., Lippincott Williams & Wilkins, - 2007.
