Formation of lamellar bodies in rat liver mitochondria in hyperthyroidism

Abstract

In the present work, ultrastructural changes of rat liver mitochondria in hyperthyroidism were studied. Hyperthyroidism was induced in male Wistar rats by daily administration of 100 μg thyroxin per 100 g body weight for 5 days. The level of triiodothyronine and thyroxine increased 3- and 4-fold, respectively, in comparison with the same parameters in the control group, indicating the development of hyperthyroidism in experimental animals. It was found that under this experimental pathology 58% of the mitochondria are swollen, with their matrix enlightened, as compared to the control. In 40% of the profiles, the swollen mitochondria in the liver under hyperthyroidism exhibited rounded mono- or multilayer membrane structures, called lamellar bodies (LBs), presumably at different stages of their development: from the formation to the release from the organelles. Most LBs were located in the mitochondria near the nuclear zone (27%), while their number was reduced in the part of the cell adjacent to the plasma membrane. In a number of swollen mitochondria the cristae were shown to change their orientation, being directed radially toward the center of the mitochondria. We suggested that it is the first stage of formation of LBs. The second stage can be attributed to the formation of monomembrane structures in the center of the organelles. The third stage is characterized by the fact that the membrane of the lamellar bodies consists of several layers, and in this case the bodies were located closer to the outer mitochondrial membrane. The evagination of the outer mitochondrial membrane and its connection with lamellar structure can be recognized as the fourth stage of formation of LBs. At the fifth stage the developed lamellar formations exited the mitochondria. At the same time, following the exit of LBs from the mitochondria, no damage to the mitochondrial membrane was registered, and the structure of the remaining part of the mitochondria was similar to the control. The nucleus of the hepatocyte also underwent structural changes in hyperthyroidism, exhibiting changes in the membrane configuration, and chromatin condensation. The nature and structure of the LBs, as well as their functional role in the liver mitochondria in hyperthyroidism, require further investigation.

Topology-dependent, bifurcated mitochondrial quality control under starvation

“…Besides normal tubular mitochondria, there are 2 special kinds of mitochondria generated by topological transformation: swollen and donut-shaped mitochondria. Various stresses can induce a shift from a tubular mitochondrial morphology to multiple round organelles with some or all swollen [22][23][24][25]. Mitochondrial swelling in relation to mitochondrial permeability transition pore (mPTP) opening has been observed, for example, during reoxygenation-reperfusion after hypoxia [26,27].…”

Structural and Dynamic Features of Liver Mitochondria and Mitophagy in Rats with Hyperthyroidism

“…However, HR also had mitochondria with lysed matrix (18% of the total HLM population), and the cristae in these organelles were reduced in number and shifted to the center or periphery (Figure 1E,H,I,M,P). These mitochondria were found to have multilamellar bodies [19,20] located either along the edge or inside the organelles (Figure 1E,H,I,N,P). It is possible that at the first stage of HT development the formation of MLBs is associated with an attempt to compensate for the metabolic needs of the cell.…”

Influence of a 30-day spaceflight on the structure of motoneurons of the trochlear nerve nucleus in mice

“…Mitochondria are the most labile intracellular structures [13,14]. They are among the first to change with increased activity of neurons and with damaging influences [15][16][17][18][19][20].…”