Der Einfluß des Perfusionsdruckes bei der Perfusionsfixation auf die Feinstruktur der Lebersinusoide. Transmissions- und rasterelektronenmikroskopische Untersuchung

Abstract

The fixation of rat liver by perfusion with glutaraldehyde with different pressures has been investigated. For this study adult male albino rats were used. Rat livers were fixed by perfusion through the abdominal aorta according to the method of FORSSMANN et al. (1967). Perfusion pressures varied from 30 to 210 mmHg. A continuous complete endothelial lining of liver sinusoids could be visualized with TEM and SEM after fixation with perfusion pressures lower than 100 mmHg. Three different regions could be noticed in the endothelial cell: 1. prominent nucleous region, 2. compact cytoplasmic processions containing mitochondria and ergastoplasma, 3. delicate fenestrated cytoplasmic areals. As a rule the fenestrations were localized in groups, s.c. sieve plates. After perfusion fixation with pressures above 100 mmHg the endothelial lining of liver sinusoids appeared similar to a wide-meshed net. The sieve plates were destroyed, and numerous defects could be found in the endothelial cells. Hepatocytes showed vacuoles which seem to be due to invagination of the cellular membrane. For the development of artifacts even with physiological perfusion pressures in the aorta (110 mmHg), the content of procaine in the rinsing solution is responsible. Eliminating the function of arteriols leads to unphysiological pressure effects in the sinusoids.

Problems with the preparation of blood vessels for scanning electron microscopy a critical review

“…This happens in a very critical phase of preparation, since the sensitive, unfixed endothelial cell is influenced in different ways by the varying chemical composition, osmolarity, temperature, and pH of these rinsing solutions, as well as by the duration of the washing process itself. Instructions like Ringer's solution (Bjorkerud et al 1972), Ringer-glucose-solufion (Brylock et al 1977, NaCl (Dujovny et al 1978), lactated Ringer's solution (Thurston et al 1976), heparinized Tyrode-Procain solution (Frenzel et al 1976) or "isotonic balanced salt solution" ) are, therefore, too general and of little value in comparing different studies. The most typical rinsing solutions are:…”

“…In recent years the perfusion method has prevailed more and more (Buss et al 1973, Buss and Hollweg 1977, Buss et al 1976, DeBruijn and VanMourik 1975, Edanaga 1974, Elemer et al 1976, Fishman et al 1975, Fonkalsrud et al 1976, Frenzel et al 1976, Hess and Staubli 1963, Shimamoto 1974, Svendsen and Jorgensen 1978, Webster et al 1974). Unfortunately there are also additional methodological variations and possibilities of error involved in this more complicated technique, making comparisons more difficult.…”

“…1). Values of the osmolarity of the solutions are still only to be found in isolated studies (Buss and Hollweg 1977, Frenzel et al 1976, Hollweg et al 1978, Kawamura et al 1974, Riede and Villiger 1970, Svendsen and Jorgensen 1978, Van Benthuysen et al 1977.Zsotonic (Davies et al 1976, Shimamoto 1974 or physiological are certainly very vague statements to be evaluated differently from case to case. In certain circumstances the physiological conditions vary in different sections of the identical vessel system, and there may be important differences between species (Hollweg et al 1978).…”

“…There are likewise data concerning the location of the outflow but not about its dimensions. It is clear that the exact examination of this problem is urgent when one considers that only non-physiological, low perfusion pressures lead to an excellent conservation of, for example, the endothelium of the liver sinusoids, while the physiological pressure of 146mbar causes artifacts, destruction of the filter plates and confluence of pores (Frenzel et al 1976). Our own current perfusion experiments with pressure registration in the carotid arteries of rabbits indicate that the driving pressure proximal to the needle, in the needle, and in the contralateral carotid artery demonstrate large deviations from one another.…”

“…Other substances used prior to and in addition to the fixative are procaine (Frenzel et a]. 1976, Peine and Low 1975, Van Benthuysen et al 1977 andxylocaine (Thurston et al 1976).…”