Electron microscopic and histochemical observations of muscle degeneration after tourniquet

Severe Fat Accumulation in Multiple Organs in Pediatric Autopsies: An Uncommon but Significant Finding

Background The observation of fat accumulation in different organs at pediatric autopsy may help determine the cause of death. However, a comprehensive study on fat accumulation and related etiologies is still lacking. Aim To investigate the incidence of fat accumulation in different organs in pediatric autopsies and their relevance to the cause of death. Methods From February 2004 until March 2015, fat accumulation was assessed in 561 routinely performed pediatric autopsies in our center. Age at death ranged from 14 weeks of gestation for fetuses to 16 years. Samples of liver, heart, kidney, and muscle were stained with Oil-Red-O and scored for fat accumulation by one pediatric pathologist. Results Fat accumulation in ≥1 organ(s) was present in 132 (39.8%) of 332 prenatal cases. Only 3 (0.9%) had fat accumulation in all 4 organs. For postnatal cases, fat accumulation in ≥1 organ(s) was present in 106 (46.3%) of 229 postnatal cases. Only 12 (5.2%) had fat accumulation in all 4 organs. Fat accumulation was mostly seen in liver, both in prenatal and postnatal cases. Fatty acid oxidation disorders were the only cause of death associated with severe fat accumulation in all 4 organs. No other etiologies could be linked directly to distribution or severity of fat accumulation. Conclusion Severe fat accumulation in at least 4 organs is a rare finding in pediatric autopsies, whereas fat accumulation in only the liver is relatively common. Severe fat accumulation in both liver, muscle, kidney, and heart was only seen in cases with fatty acid oxidation disorders.

Histopathological muscle findings may be essential for a definitive diagnosis of suspected sharp trauma associated with ship strikes in stranded cetaceans

Ship strikes are a major issue for the conservation of may cetacean species. Certain gross and microscopic criteria have been previously reported for establishing a diagnosis of death due to ship strikes in these animals. However, some ship-strike injuries may be masked by advanced carcass decomposition and may be undetectable due to restricted access to the animals. In this report we describe histopathological muscular findings in 13 cetaceans with sharp trauma from ship strikes as the cause of death. Skeletal muscle samples were taken from the incision site and from the main locomotor muscle, the longissimus dorsi, in areas not directly affected by the sharp injury. The microscopic findings in tissues from both sites mainly consisted of haemorrhages; oedema; flocculent, granular or/and hyalinised segmentary degeneration; contraction band necrosis; and discoid degeneration or fragmentation of myofibres. We propose that skeletal muscle histopathology provides evidence of ante-mortem injuries even if the sample was taken elsewhere in the carcass and not only within or adjacent to the sharp trauma site and despite the advanced decomposition of some of the carcasses. This method helps to establish the diagnosis of ship strike as the cause of death.

Muscle fiber viability, a novel method for the fast detection of ischemic muscle injury in rats

Acute lower extremity ischemia is a limb- and life-threatening clinical problem. Rapid detection of the degree of injury is crucial, however at present there are no exact diagnostic tests available to achieve this purpose. Our goal was to examine a novel technique - which has the potential to accurately assess the degree of ischemic muscle injury within a short period of time - in a clinically relevant rodent model. Male Wistar rats were exposed to 4, 6, 8 and 9 hours of bilateral lower limb ischemia induced by the occlusion of the infrarenal aorta. Additional animals underwent 8 and 9 hours of ischemia followed by 2 hours of reperfusion to examine the effects of revascularization. Muscle samples were collected from the left anterior tibial muscle for viability assessment. The degree of muscle damage (muscle fiber viability) was assessed by morphometric evaluation of NADH-tetrazolium reductase reaction on frozen sections. Right hind limbs were perfusion-fixed with paraformaldehyde and glutaraldehyde for light and electron microscopic examinations. Muscle fiber viability decreased progressively over the time of ischemia, with significant differences found between the consecutive times. High correlation was detected between the length of ischemia and the values of muscle fiber viability. After reperfusion, viability showed significant reduction in the 8-hour-ischemia and 2-hour-reperfusion group compared to the 8-hour-ischemia-only group, and decreased further after 9 hours of ischemia and 2 hours of reperfusion. Light- and electron microscopic findings correlated strongly with the values of muscle fiber viability: lesser viability values represented higher degree of ultrastructural injury while similar viability results corresponded to similar morphological injury. Muscle fiber viability was capable of accurately determining the degree of muscle injury in our rat model. Our method might therefore be useful in clinical settings in the diagnostics of acute ischemic muscle injury.

Ischaemia and reperfusion effects on skeletal muscle tissue: morphological and histochemical studies

This was a study on the oxidative stress due to ischaemia (I) and reperfusion (R) in skeletal muscle tissue. Using a tourniquet, groups of rats were submitted to ischaemia for 4 h, followed by different reperfusion periods. The animals were divided in four groups: control; 4 h of ischaemia (IR); 4 h of ischaemia plus 1 h reperfusion (IR-1 h); 4 h of ischaemia plus 24 h reperfusion (IR-24 h); and 4 h of ischaemia plus 72 h reperfusion (IR-72 h). At the end of the procedures, samples of soleus muscle were collected and frozen in n-hexane at -70 degrees C. Cryostat sections were submitted to haematoxylin-eosin, succinate dehydrogenase (SDH) and nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR) stains. An additional muscle sample was processed for electron microscopy. No alterations were found in control animals. IR group showed fibres had normal aspect besides some round, acidophilic and hypertrophic fibres. There were several fibres with angular outlines and smaller diameters in this group compared with control group. NADH-TR/SDH reaction was moderately intense in most fibres. In some fibres, cytoplasm showed areas without activity and other fibres had very intense reactivity. IR-1 h group showed oedema hypercontracted fibres with disorganized myofibrils, mitochondria with focal lesions and dilated sarcoplasmic reticulum. NADH-TR/SDH reaction was moderate to weak. IR-24 h showed intense inflammatory infiltrate in the endomysium and perimysium. NADH-TR/SDH reaction was similar to IR-1 h. IR-72 h showed necrotic fibres, areas with inflammatory infiltrate, reduced muscle fibres at different stages of necrosis and phagocytosis, and many small round and basophilic fibres characterizing a regeneration process. NADH-TR/SDH reaction was weak to negative. Our results suggest that ischaemia and the subsequent 1-, 24- and 72-h reperfusions induced progressive histological damage. Although progressive, it may be reversible because there were ultrastructural signs of recovery after 72-h reperfusion. This recovery could in part be due to the low oxidative stress identified by the morphological and histochemical analysis.

Pathology study of rabbit calf muscles after repeated compression

: To elucidate the pathogenesis of chronic compartment syndrome, we examined pathological changes in the soleus (red) and extensor digitorum longus (EDL; white) muscles in Japanese white rabbits after repeated compression with a pneumatic tourniquet. Repeated tourniquet compression via cuff inflation was carried out on the rabbits, calves daily, for 2 h, then stopped for 30 min, and then applied for another 2 h. The contralateral hindlimb, which was not compressed, served as a control. Animals were allocated to 15 groups, with pressures of 40, 80, and 120 mmHg for periods of 1 day, 3 days, 1 week, 2 weeks, and 4 weeks. Skeletal muscle specimens in each group were studied by histopathological and histochemical (ATPase) methods. After compression for 1 day, regardless of pressure, and compression for 3 days in the 40-mmHg pressure group, edematous changes in regions with mild inflammation and increases in fiber diameter were observed in the muscles. After compression for 3 days in the 80- and 120-mmHg pressure groups, and after 1, 2, or 4 weeks in the 40-mmHg pressure group, a few necrotic fibers and scattered fibers with some mononuclear cell infiltrates indicative of early-stage necrosis were detected. In the groups with 80 or 120 mmHg pressure for 1, 2, or 4 weeks, muscle fibers exhibited marked degenerative changes, which were more pronounced in the 120-mmHg group than in the 80-mmHg group. The pathological changes were more pronounced in the soleus than in the EDL muscles, indicating that these two muscles differed in sensitivity to repeated compression. Additionally, average muscle wet weight and average fiber diameter for both types of muscle were increased in the 1-day and 3-day compression groups and decreased in the 1-week, 2-week, and 4-week compression groups. These findings clearly differ from those of previously reported single-compression experiments. Our findings indicate that repeated compression may cause serious muscle degeneration, particularly in red muscles.

Contractile properties of slow and fast muscle following tourniquet ischemia

Tourniquet application is commonly used during surgery on an extremity to create a bloodless field. Investigations have focused on the ultrastructural, histochemical, and biochemical effects of tourniquet ischemia on muscle. Few studies, however, have examined the influence of tourniquet ischemia on the contractile properties of muscle. The purpose of this study was not only to examine this latter consideration, but also to determine whether slow and fast muscles exhibit a differential response. In adult male guinea pigs, the plantaris and soleus muscles of control (N = 5) and experimental legs (N = 5) were tested for time-peak-tension (TPT), one-half relaxation time (1/2RT), maximal twitch tension (Pt), and maximal tetanic tension (Po). The experimental leg was subjected to a 2 hour tourniquet which was placed around the thigh. Muscles of this leg were tested following a 2 hour recovery period. In three of the five animals, no response could be elicited from either the plantaris or soleus muscles of the experimental leg. In those instances where the experimental muscles were capable of generating force, the plantaris was clearly more effected. While tension production in the soleus was reduced by approximately 55%, the plantaris exhibited approximately a 90% decrease in tension output. Furthermore, both TPT and 1/2RT demonstrated consistent changes. These results indicate that the contractile properties of both the soleus and plantaris are dramatically effected by a 2 hour tourniquet. They further suggest that there may be a differential response based upon fiber type.

Post-ischemic calcification in skeletal muscle. A light microscopic study in the rat

The extent of post-ischemic calcification in skeletal muscle was studied in rats subjected to 5.5 h of ischemia followed by periods of reperfusion ranging from 30 min to 16 h. Sections from the tibialis posterior and soleus muscle were stained with alizarin red S (ARS) and were inspected with light microscopy. The number of ARS-positive cells increased during the first 5 h of reperfusion. The extent of calcification varied between fibers and the pattern of calcification appeared to be dependent on fiber type. In some fast glycogenolytic fibers (FG) central calcifications, probably representing mitochondria, were observed. In fast oxidative glycogenolytic (FOG) and slow oxidative (SO) fibers the most common pattern was an ARS-positive granulation, probably representing calcification of sarcoplasmic reticulum and/or mitochondria. The granulation was more extensive in FOG than in SO fibers. In some areas extracellular ARS-positive material was observed. In such areas, which probably represent areas of no-reflow, no calcification of muscle fibers was observed.

Effect of ischemia on contractile and histochemical properties of the rat soleus muscle

Ligature and section of the abdominal aorta results in only minor and temporary functional and metabolic changes in the slow soleus muscle of the rat. A very small decrease in maximal tetanic tension corresponds to a few scattered areas of damaged and necrotic muscle fibres, in which decreased succinic dehydrogenase and loss of phosphorylase activity was observed. A new experimental approach, i.e. ligature and section of the abdominal aorta combined with terminal devascularisation, preserving intact tendons and innervation of the muscle causes maximal muscle ischemia, followed by an almost complete loss of tetanic tension output, marked shortening of contraction time and profound morphological and histochemical changes. The decrease in succinic dehydrogenase and ATPase activities and loss of phosphorylase activity occur in the majority of degenerating muscle fibres except for a thin rim of peripheral fibres during the first 4 days. Subsequently, the contractile properties recover gradually and enzyme activities reappear in the regenerating muscle fibres simultaneously with new revascularisation. Thirty days after the operation all the parameters observed returned to control values.

Effects of ischaemia on enzyme-activities in the soleus muscle of the rat

1. The changes with the time of the activities of some energy-supplying enzymes and of the hydrolytic enzyme, acid phosphatase, were studied over 2 weeks of complete ischaemia, produced in the rat soleus muscle by section of the abdominal aorta and terminal devascularization, leaving nerve and tendon intact. 2. Activities of glycolytic enzymes, oxidative enzymes, hexokinase and acid phosphatase are affected in a different manner. Activities of the glycolytic enzymes, lactate dehydrogenase, triosephosphate dehydrogenase and glycerolphosphate dehydrogenase, are lowest on the 1st day and increase thereafter. The first two reach the control values again on the 4th and 14th day, respectively, while glycerolphosphate dehydrogenase reaches about 50% of the control value on the 14th day. The maximum decrease in activity of the oxidative enzymes, citrate synthase, beta-hydroxyacyl-CoA-dehydrogenase and malate dehydrogenase occurs later (4th day); thereafter their activity returns slowly to control values, but does not reach them even on the 14th day. Hexokinase activity is slightly decreased on the 1st day; then it increased and reached on the 7th day twice the control value. Thus on the 1st day the activity of the enzymes of aerobic metabolism prevail, and on the 4th day those of anaerobic carbohydrate (glucose) metabolism; the recovery of enzyme activity of aerobic oxidation occurs later. 3. Acid phosphatase activity increased from the 2nd day onwards, reaching up to 3 times the control value on the 4th day and still twice that value on the 14th day. This agrees well with the histochemical picture of acid phosphatase. 4. Histochemical changes of alkaline phosphatase activity reveal destruction of capillary endothelial cells during the first few days after operation and their later proliferation from the periphery, correlating with the loss and recovery of oxidative enzyme activity.

The early effects of ischemia upon skeletal muscle mitochondria

The effects of early ischemia were studied in the anterior tibial muscle of Sprague-Dawley rats after 2--24 hr of tourniquet compression at the thigh. Ragged-red fibers, moth-eaten fibers, cores and targets were seen in tissue examined by enzyme histochemistry and electron microscopy. Giant mitochondria, abnormalities of cristal arrangement, crystalloids, osmiophilic inclusion bodies and myeloid figures were dominant features of the mitochondrial reaction. The results of this experiment indicate that early ischemia induces a variety of changes described in other neuromuscular conditions such as dystrophy and the "mitochondrial myopathies". The pathogenesis of these changes and their relationship to human disease of muscle is discussed.

The morphogenesis of beta-aminopropionitrile-induced rib malformation in fetal golden Syrian hamsters

In order to provide information on the mechanism of beta-aminopropionitrile (betaapn) induced teratogenesis, the pathogenesis of a fetal rib abnormality was studied at relatively short time intervals following maternal treatment with 2,500 mg/kg aqueous betaapn on day 11 of gestation. Histochemical tests of ribs from betaapn-exposed fetuses indicated a slight decrease in the level of glycosaminoglycans but at a time when the defect was already morphologically established. Ultrastructural observations on the chondrocytes of ribs from betaapn-exposed fetuses revealed alterations in mitochondrial structure indicative of a slight cytotoxic effect for the teratogen. The mitochondrial changes were transient, occurring initially at three hours after treatment and lasting for nine hours. Alterations in the size of collagen fibres in the cartilage of the fetal rib were also observed in the offspring of betaapn treated females. The mean diameter of collagen fibres in the ribs of control fetuses increased throughout the course of the study. The mean diameter of fibres in the fetuses of betaapn-exposed females failed to show any increase and was found to be significantly less than controls as early as three hours following maternal administration. The results suggested that the principal factor in the production of the fetal rib deformity was fundamentally the same as that known to affect the adult; namely a defect in the extracellular maturation of collagen.

Ultrastructure of striated muscle of the rat after temporary ischemia

Twenty-six anterior tibial muscle specimens were analyzed with the electron microscope 2 h, 1, 4, 18, 45, 90 and 226 days after temporary ischaemia of the rat hind leg produced by pneumatic tourniquet for 1, 2, 3, 4 and 6 h. No ultrastructural alterations were seen after 1 h ischaemia, but reversible disappearance of muscle glycogen and swelling of muscle and nerve mitochondria occurred after 2 h ischaemia. Irreversible alterations such as disappearance of the Z-line, disruption of cell membrane and vacuolation of muscle mitochondria were observed after ischaemia of 3 h and longer in a part of the muscle fibres. Ischaemia for 6 h was followed by autolysis of all the muscle fibres within the specimens. Autolysis and phagocytosis of the remnants of the affected fibres was present on the 4th day. On that day regenerative phenomena were also observed, such as satellite cells and young myotubes. The fine structure of the muscle fibres was normal on the 18th day after the temporary ishcaemia, although some size variation of the muscle fibres was still observed. Degeneration of a part of the presynaptic nerve endings of motor end-plates with or without simultaneous degeneration of the postsynaptic muscle fibre was seen after ischaemia lasting 3 h or longer. Motor end-plates were first seen on the 45th day in the muscle subjected to 6 h ischaemia and were most likely regenerated ones.

Histochemical studies of striated muscle after temporary ischemia in the rat

Temporary ischaemia of the hind linb of the rat was produced using a tourniquet with controlled pressure. Changes in the muscle seen after Gomori trichrome staining and after histochemical reactions for NADHdiaphorase, ATPases and phosphorylase were correlated with the duration of the ischaemia and the time of recovery. Histopathological changes were seen first after 2 h of ischaemia and increased thereafter; necrosis of most of the muscles occurred between 4 and 6 h of ischaemia. Necrosis and phagocytosis of muscle fibres and later the amount of regenerating fibres with characteristic histochemical staining properties increased linearly with increasing duration of ischaemia. Even after the most severe lesions of seemingly total necrosis of the muscle after 6 h of ischaemia most of the muscle regenerated within 18 days. Morphological alterations such as variation in fibre size, split fibres and central nuclei were still observed 226 days after ischaemia at which time the follow-up was terminated. Fibre type grouping was seen first after 45-90 days subsequent to 4 and 6 h ischaemia after incubation for ATPase, indicating concomitant neurogenic lesion in addition to the direct ischaemia of the muscle fibres.

The effect of the local anaesthetic bupivacaine on the muscle spindle of rat

The effects of a long-lasting local anaesthetic, bupivacaine, in combination with hyaluronidase, on the intrafusal muscle fibres of adult rat muscle spindles have been investigated by light and electron microscopy. Necrotic changes in the axial bundle are present within 4 h of the combined drug injection and are widespread by 2 days. The equatorial nucleation of the spindle is lost owing to the necrosis of the myonuclei. Satellite cells, however, appear to survive these changes, even where the underlying muscle fibres are grossly necrotic. Sensory nerve terminals undergo necrosis during this period and plate-type fusimotor nerve terminals withdraw from the degenerating muscle fibres. Macrophage infiltration and early regeneration of the axial bundle is apparent by the third day. Myoblasts first appear at the periphery of the affected muscle fibres, but decrease in number as regeneration proceeds. By the end of the third week, regeneration of the muscle component is complete and re-innervating fusimotor nerve terminals established. The encapsulated regions of the spindle remain abnormal, without recognizable bags or chains of nuclei, although the muscle fibres differ both in size and ultrastructure. Regenerating sensory axons make contacts with the intrafusal bundle that differ in their configuration and ultrastructure from normal terminals. The production of enucleated spindles is discussed in the light of the morphogenetic influences of the spindle nerve terminals, as well as the possible use of such a model in discovering the function of nuclear bags and nuclear chains.

Evaluation of the isolated perfused rat hindquarter for the study of muscle metabolism

1. The metabolic integrity of a new isolated rat hindquarter preparation was studied. The hindquarter was perfused with a semi-synthetic medium containing aged human erythrocytes. More than 95% of the oxidative metabolism of the preparation was due to muscle, the remainder being due to bone, adipose tissue and, where present, skin. 2. Consumption of O(2), glucose utilization, glycerol release and lactate production were similar in the presence and in the absence of the skin, indicating that the latter contributed little to the overall metabolism of the preparation. 3. After 40min of perfusion, tissue concentrations of creatine phosphate, ATP and ADP were similar to those found in muscle taken directly from intact animals. The muscle also appeared normal under the electron microscope. 4. The hindquarter did not lose K(+) to the medium during a 30min perfusion. In the presence of insulin it had a net K(+) uptake. 5. Insulin caused a sixfold increase in glucose uptake, stimulated O(2) consumption by nearly 40% and depressed glycerol release to less than half the control value. 6. Bilateral sciatic-nerve stimulation caused severalfold increases in O(2) consumption and lactate production. In the absence of insulin nerve stimulation also enhanced glucose uptake; in the presence of insulin it did not further increase the already high rate of glucose uptake. 7. Rates of lactate production and O(2) consumption of the rat hindquarter in vivo and the isolated perfused hindquarter were very similar. 8. Ketone bodies were a major oxidative fuel in vivo of the hindquarter of a rat starved for 2 days. If the acetoacetate and 3-hydroxybutyrate removed by the tissue were completely oxidized, they would have accounted for 77% of the O(2) consumption. 9. Acetoacetate accounted for 84% of the ketone bodies removed by the hindquarter in vivo even though its arterial concentration was half that of 3-hydroxybutyrate. 10. Similar rates of acetoacetate and 3-hydroxybutyrate utilization were observed in the perfused hindquarter. 11. Acetoacetate utilization by the perfused hindquarter was not diminished by the addition of either oleate or insulin to the perfusate. 12. Oxidation of glucose to CO(2) accounted for less than 4% of the O(2) consumed by the perfused hindquarter in both the presence and the absence of insulin. 13. The results indicate that the isolated perfused hindquarter is a useful tool for studying muscle metabolism. They also suggest that ketone bodies, if present in sufficient concentration, are the preferred oxidative fuel of resting muscle.

The value of electron microscopy in muscle biopsies

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Progress in disseminated intravascular coagulation. II

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CARDIAC NECROSIS AND CALCIFICATION IN EXPERIMENTAL MAGNESIUM DEFICIENCY. A LIGHT AND ELECTRON MICROSCOPIC STUDY

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Ultrastructural and physiologic alterations in ischemic skeletal muscle

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Factors Involved in Recovery from Experimental Skeletal Muscle Ischemia Produced in Dogs: I. Histologic and Histochemical Pattern of Ischemic Muscle

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Ultrastructure of human muscle

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