Einfluß einer Bleibelastung auf die quantitative Cytoarchitektur der Leberzelle juveniler Ratten

TLDR: The quantitative changes of the endoplasmic reticulum and in the number of free ribosomes (polysomes) as well as the fingerprint-like membrane whorls indicate an interference of lead with protein synthesis.

Abstract: Introduction Even small quantities of lead inhibit the respiratory chain and the hemoglobin synthesis as well as the gluconeogenesis. Lead is concentrated in mitochondria and lysosomes. Therefore, it was of interest to analyse morphometrically the adaptability of liver parenchymal cells of juvenile rats to lead overload. Material and Methods 20 10-day-old male Wistar rats were used — During 2 weeks, 15 of these animals were injected i. p. 0,2 ml of a 1% lead acetate solution. Afterwards they were seperated from their mothers and given free access to food and tap water. During 2 additional weeks lead acetate was added to the tap water. 5 untreated rats served as controls. After 4 weeks the animals were sacrified. Morphometric analysis was made according to Weibel et al., 1969. Results After 4 weeks of lead overload, nuclear invaginations and intranuclear lipid inclusions occur. Giant lysosomes contain osmiophilic granular material and damaged mitochondria. Fingerprint-like mebrane whorls can be observed. The number of mitochondria per unit volume of cytoplasm decreases without changes in mean volume of mitochondria. The total surface of cristae per unit cytoplasmic volume increases by 20%. The RER increases its mebranes and volume by 50%. The volume of the free ribosomes increases, too. SER and lysosomes lose part of their volume. Discussion Under the influence of a 4 week lead overload a change in nuclear morphology occurs. The number of mitochondria decreases probably due to blocked chondriogenesis. The proliferation of cristae membranes is considered a consequence of a disintegrated membran formation. The quantitative changes of the endoplasmic reticulum and in the number of free ribosomes (polysomes) as well as the fingerprint-like membrane whorls indicate an interference of lead with protein synthesis.