Effect of helium-neon laser radiation on restoration of the structure of the microcirculatory bed and neurocytes of the small intestine following experimental ischemia

Influence of helium-neon laser lg-75 rays on the microcirculatory bed and neurocytes of the small intestine after its experimental ischemia has been studied. When a normal small intestine is radiated, dilatation of the luminal diameter is observed in all links of the microcirculatory bed (MCB) and also hypertrophy of neurocytes, when phenomena of distrophic processes are absent. In 30 days after 3-hours' ischemia of the intestinal loop and its successive radiation, spasm of arterial and dilatation of the venous link of MCB is registered; they normalize by the 45th day. In the control, after ischemia (without radiation) in 45 days venous plethora of the vessels in the intermuscular plexus of the intestinal wall is kept. In the nervous elements of the muscular-intestinal plexus at early stages of the experiment against the background of ischemia reactive and distrophic changes appear. By the 30th day after radiation, the volume of neurocytic bodies increases, processes grow out, nuclear-cytoplasmic index increases. Nonspecific character of the laser rays is supposed; their effect is realised via regional microvascular and nervous formations.     

Ultrastructural changes in the components of the filtration barrier in the glomerular capillaries of a remaining kidney following its temporary ischemia

The components of the filtration barrier of the glomerular capillaries of the rat remaining kidney were studied ultrastructurally 3, 7, 14, 30, 60, 180 and 360 days after exposure to 30 minutes and to 1-2 hours of ischemia. Submicroscopic changes found in the glomerular capillaries and in compensation -adaptive processes occurring in the remaining kidney were ascertained to be dependent on the duration of ischemia and the time elapsed since recirculation in the kidney. After 30-minute ischemia experienced by the remaining kidney the structural alterations in the glomerular capillaries were not remarkable, disappearing 14 days following recirculation, with the emergence by that time of the signs of hyperplasia and hypertrophy of intracellular structures. After raising the time of temporary ischemia of the remaining kidney up to 60 min followed by recirculation, appreciable ultrastructural postischemic disorders were recorded in the components of the filtration barrier of the glomerular capillaries. In addition, the compensation-adaptive processes in the kidney remained suppressed for a longer period of time. All these disorders were particularly demonstrable as a result of 2-hour ischemia. It was also discovered that destructive processes dominated over reparative ones thereby leading to the animals' death at early times of experiment.     

Morphological evaluation of the state of the structural elements of arterial and arteriolar walls in experimental kidney ischemia

Resetting of arterial and arteriolar wall structural components have been studied in the white rat kidney glomeruli after experimental ischemia (30 min, 1-3 h) without blood flow recovery and with the following recirculation for 3-30 days. The experiments have established that acute renal ischemia caused by the vascular leg ligation for 30-60 min without the following blood flow recovery results in slight microstructural alterations of arterial and arteriolar wall elements. With increased ischemia duration (2-3 h) pathological changes become more prominent and separation of vascular endothelial cells and defibering of the internal elastic membrane take place. In transitory (30-60 min) ischemia of the remaining kidney (one kidney is removed) three days later desquamation of endothelial cells occurs in some arteries. Thinning of arterial walls and overstrain of internal elastic membrane are observed. However, later on (in 30 days) short-term ischemia (30 min) is followed by complete recovery of structural components of arterial and arteriolar walls. In more durable ischemia (2-3 h) of the remaining kidney the recovered blood flow causes marked destructive life-threatening changes in vascular walls.     

Effect of helium-neon laser on the microcirculation in blood vessels of the rat pia mater

The sensitivity of rat's microvessels of microcirculatory bed of brain's pia matter was studied by helium-neon laser radiation. Changes in the reactivity by the microscopy findings were studied on the 7, 30, 45, 60, 90th days of animals postnatal development. Laser radiation was used during 30 min. Local changes in all components of the microcirculatory bed were fixed. It is mentioned that in adult rat the expressiveness of arteriole's local widening reaction in the radiated place reduces, but the degree of the reduction is below or over the radiated place, on the contrary, increases. The arteriole diameter in 30-day old rats increases to 59% in comparison to the initial level, and 90th day old animals--to 16%. The degree of reaction's expressiveness depends upon the microvessel diameter and the animal's age.     

Pancreatic damage and regeneration in the course of ischemia-reperfusion induced pancreatitis in rats.

The objective of this study was to assess the biochemical and histological signs of pancreatic damage development and pancreatic recovery in the course of ischemia-reperfusion induced pancreatitis. Acute pancreatitis was induced in rats by limitation of pancreatic blood flow (PBF) in inferior splenic artery for 30 min using microvascular clips, followed by reperfusion. Rats were sacrificed at the time: 1 h, 12 h, 24 h, and 2, 3, 5, 7, 10, 14, 21 and 28 days after ischemia. PBF was measured using laser Doppler flowmeter. Plasma amylase, interleukin 1beta (IL-1beta) and interleukin 10 (IL-10) concentration, pancreatic DNA synthesis, as well as, morphological features of pancreatic damage were examined. Ischemia with reperfusion caused acute necrotizing pancreatitis followed by pancreatic regeneration. After removal of microvascular clips, PBF was reduced and the maximal fall of PBF was observed 24 h after ischemia, then PBF grew reaching the control value at 28th day. Plasma amylase activity was increased between 12th h and 3rd day with maximum at 24 h after ischemia. Also plasma IL-1beta and IL-10 were elevated with maximal value at the first and second day after ischemia, respectively. DNA synthesis was maximally reduced at the first day (by 70%) and from second day the reversion of this tendency was observed with full restoration of pancreatic DNA synthesis within four weeks. Morphological features of pancreatic tissue showed necrosis, strongly pronounced edema and leukocyte infiltration. Maximal intensity of morphological signs of pancreatic damage was observed between first and second day of reperfusion. During pancreatic regeneration between second and tenth day after ischemia the temporary appearance of chronic pancreatitis-like features such as fibrosis, acinar cell loss, formation of tubular complexes and dilatation of ducts was observed. The regeneration was completed within four weeks after pancreatitis development. We conclude that partial and temporary pancreatic ischemia followed by reperfusion causes acute necrotizing pancreatitis with subsequent regeneration within four weeks. Pancreatic repair after necrotizing pancreatitis is connected with the increase in plasma IL-10 concentration and transitory formation of tubular complexes.     

Fate of the juxtaglomerular complex after ischemic injury

The juxtaglomerular (JG) complex was studied at different times after 90 min of warm kidney ischemia: 2 h, 24 h, 3 days, 10 and 30 days following the ischemia. The ischemic injury was performed on the left kidney, under two experimental conditions: with and without previous nephrectomy of the contralateral nonischemic kidney. The activity of the JG complex was evaluated by assessing the JG index and by determination of plasma renin activity. Results show that, under given experimental conditions, fate of the particular JG complex depends on the fate of its own nephron. In the presence of the contralateral intact kidney most nephrons of the ischemic kidney underwent gradual degeneration and their JG complexes degenerated too. When ischemic kidney was the sole kidney, the majority of nephron units regenerated and their JG complexes recovered both morphologically and functionally.     

Structural and functional state of the renal transplant after spontaneous and surgical restoration of the lymph outflow pathways

In 62 dogs, presenting a model of the renal autotransplantation into the pelvis on the iliac vessels, a comparative estimation of morpho-functional state of the transplanted organ has been performed at a spontaneous (control) and surgical (experiment) restoration of the lymphatic outflow pathways during the postoperative period from 1 day up to 6 years. Three periods of morpho-functional restoration of the transplant renal tissue have been revealed: I (period of decreased functional activity) lasts in the control from 1 up to 14 days, in the experiment--up to 7 days after the operation; II (period of restoration of the functional activity) lasts in the control from 14 up to 90 days, in the experiment--from 7 up to 30 days after the operation; III (steady functioning of the renal transplant) begins in the control on the 90th day, in the experiment--on the 30th day after the operation and lasts up to the end of the observations. Such signs as lymphostasis and certain disturbances of oxidation-reduction and physical-chemical processes in the renal tissue are specific features. Time of normalization of the processes mentioned and degree of their manifestation depend on spontaneous or surgical restoration of the lymphatic outflow pathways. The surgical relymphatization of the renal transplant contributes to a more rapid and complete restoration of its morphofunctional state in comparison to a traditional method of the kidney transplantation.     

Effects of thermal factors on the state of microcirculation of the small intestine in acute ischemia

The influence of normo- (38 degrees C), hyper- (42 degrees C) and hypothermia (20 degrees C) on microcirculatory disturbances caused by acute local ischemia of the small intestine was investigated with the help of biomicroscopy as well as morphological methods. Ischemia was modeled by ligation of the intestine look eventrated through the abdominal wall incision of a rat onto the microscope stage for 1 h. It was shown that hyperthermia intensified microcirculatory disorders and stimulated destructive processes in tissues and hypothermia promoting microcirculation and decreasing metabolism and restrained the development of these processes. Important peculiarity of the microvascular response to ischemia, hyper- and hypothermia was revealed: heterogeneity of the reaction of different parts of microvascular bed. Appropriate evaluation of the microcirculation state in such conditions can be obtained taking into account not only the qualitative character of microvascular reaction but also an extent of this reaction manifestation in different parts of microvascular bed.     

Influence of global ischemia on the sarcolemmal ATPases in the rat heart

To elucidate the effect of global ischemia on the energy utilizing processes, regarding the molecular principles, the kinetic and thermodynamic properties of the sarcolemmal ATPases were investigated in the rat heart. The activation energy for hydrolysis of ATP during ischemia was higher when the reaction was catalyzed by Ca-ATPase or Mg-ATPase. For the Na,K-ATPase reaction, no changes in the activation energy were observed. With respect to the enzyme kinetics, ischemia in a timedependent manner induced important alterations in K_M and V_max values of Na,K-ATPase, Ca-ATPase and Mg-ATPase. The V_max value decreased significantly already after 15 min of ischemia, and it also remained low after 30, 45 and 60 min for all 3 enzymes. The significant diminution of K_M values occurred later in the 30th min for Ca-ATPase, in the 45th min for Na,K-ATPase. The observed drop in K_M indicates the increase in the affinity of the enzymes to substrate, suggesting thus the adaptation to ischemic conditions on the molecular level. This effect could be attributed to some conformational changes of the protein molecule in the vicinity of the ATP-binding site developing after longer duration of ischemia.     

Extract EGb 761 Pretreatment Limits Ubiquitin Positive Aggregates in Rabbit Spinal Cord Neurons after Ischemia-Reperfusion

1. Ubiquitin immunohistochemistry was used for investigation of time dependent changes of ubiquitin in the nerve cells reacting to ischemic/reperfusion damage. In the rabbit spinal cord ischemia model a period of 30 min ischemia followed by 24 and 72 h of reperfusion caused neuronal degeneration selectively in the ventral horn motor neurons as well as interneurons of the intermediate zone.2. Ubiquitin aggregates were accumulated in the neurons of lamina IX and the neurons of intermediate zone destined to die 72 h after 30 min of the spinal cord ischemia.3. The activation of ubiquitin hydrolytic system is related to a defective homeostasis and could trigger different degenerative processes. Having in mind this, we used EGb 761 to rescue the motor neurons and interneurons against ischemia/reperfusion damage. Our results show that after 30 min of ischemia and 24 or 72 h of reperfusion with EGb 761 pre-treatment for 7 days the vulnerable neurons in the intermediate zone and lamina IX exhibit marked elevation of ubiquitin–positive granules in the cytoplasm, dendrites and nuclei. Abnormal protein aggregates have not been observed in these cells.4. The rabbits were completely paraplegic after 30 min of ischemia and 24 or 72 h of reperfusion. However, after 7 days EGb 761 pre-treatment, 30 min of ischemia and 24 or 72 h of reperfusion the animals did not show paraplegia.5. Evaluated ubiquitin–positive neurons of the L₅–L₆ segments showed significant decrease in number and significant increase of density after 30 min of ischemia followed by 24 h and mainly 72 h of reperfusion. Ubiquitin immunohistochemistry confirmed the protective effect of EGb 761 against ischemia/reperfusion damage in the rabbit spinal cord.     

Morphofunctional adjustments in the microvasculature of the conjunctiva of the human eye at different stages of the postnatal period of ontogenesis

By means of the biomicroscopy method under vital conditions, conjunctival microvessels in the eyeball have been investigated in 240 healthy boys 7-17 years of age at the state of rest and at the antiorthostatic action. The rearrangement of the conjunctival microcirculatory bed of the eyeball completes on the whole by 13-14 years of age and is characterized by transition from diffuse to a more refulate structure (the number of the main magistrals lessens, they become larger, the number of capillaries functioning simultaneously decreases, the role of the shunting blood stream becomes more important). With this process in ontogenesis, certain changes in reactivity of microvessels are connected. The quickest and the most adequate responses of the microvessels appear in the development by the time when the definitive composition of the conjunctival microcirculatory bed in the eyeball is formed. Since that time the microcirculatory system reaches its optimal level of functioning and all the processes are performed in the most economic regimen.     

Reperfusion damages to the heart in acute transitory coronary failure and their prevention with myophedrin

Experiments were made on 56 white noninbred male rats with transitory coronary insufficiency (duration of myocardial ischemia 10, 40 and 120 min, the length of subsequent reperfusion 10 and 40 min). It was discovered that there were changes in the ultrastructure of cardiocytes and vessels of the microcirculatory bed both in the area of ischemia and reperfusion and in the distant heart regions, an increase in myocardial cell and microvessel lesions during postischemic reperfusion not only in the area of ischemia but also in distant zones. In addition, a reduction was noted in the degree of ischemic and reperfusion myocardial injury during the prophylactic use of myophedrine. The mechanisms of the protective action of myophedrine in acute transitory coronary insufficiency are discussed.     

Prevention of kidney ischemia/reperfusion-induced functional injury and JNK, p38, and MAPK kinase activation by remote ischemic pretreatment

MAPK activities, including JNK, p38, and ERK, are markedly enhanced after ischemia in vivo and chemical anoxia in vitro. The relative extent of JNK, p38, or ERK activation has been proposed to determine cell fate after injury. A mouse model was established in which prior exposure to ischemia protected against a second ischemic insult imposed 8 or 15 days later. In contrast to what was observed after 30 min of bilateral ischemia, when a second period of ischemia of 30- or 35-min duration was imposed 8 days later, there was no subsequent increase in plasma creatinine, decrease in glomerular filtration rate, or increase in fractional excretion of sodium. A shorter period of prior ischemia (15 min) was partially protective against subsequent ischemic injury 8 days later. Unilateral ischemia was also protective against a subsequent ischemic insult to the same kidney, revealing that systemic uremia is not necessary for protection. The ischemia-related activation of JNK and p38 and outer medullary vascular congestion were markedly mitigated by prior exposure to ischemia, whereas preconditioning had no effect on post-ischemic activation of ERK1/2. The phosphorylation of MKK7, MKK4, and MKK3/6, upstream activators of JNK and p38, was markedly reduced by ischemic preconditioning, whereas the post-ischemic phosphorylation of MEK1/2, the upstream activator of ERK1/2, was unaffected by preconditioning. Pre- and post-ischemic HSP-25 levels were much higher in the preconditioned kidney. In summary, post-ischemic JNK and p38 (but not ERK1/2) activation was markedly reduced in a model of kidney ischemic preconditioning that was established in the mouse. The reduction in JNK and p38 activation can be accounted for by reduced activation of upstream MAPK kinases. The post-ischemic activation patterns of MAPKs may explain the remarkable protection against ischemic injury observed in this model.     

Ultrastructure of blood capillaries in vascular plexuses of the lateral ventricles of the human brain

Ultrastructure of the wall of the microcirculatory bed links in the lateral ventricles of the human brain has been studied, as well as their interrelations with neural elements and ependyma. Together with typical morphological structural signs, certain peculiarities are revealed, characterizing organic specificity. Elements, performing function of the blood-brain barrier are determined: epithelium (ependyma), basal membranes, interstitium. A well developed afferent and efferent nervous apparatus of the vascular plexus, evidently, actively participates in regulation of the microcirculatory blood bed and in formation of liquor.     

Temporal Profile of Astrocytes and Changes of Oligodendrocyte-Based Myelin Following Middle Cerebral Artery Occlusion in Diabetic and Non-diabetic Rats

The long-term impacts of cerebral ischemia and diabetic ischemia on astrocytes and oligodendrocytes have not been defined. The objective of this study is to define profile of astrocyte and changes of myelin in diabetic and non-diabetic rats subjected to focal ischemia.Focal cerebral ischemia of 30-min duration was induced in streptozotocin-induced diabetic and vehicle-injected normoglycemic rats. The brains were harvested for immunohistochemistry of glial fibrillary acidic protein (GFAP) and 2'', 3''-cyclic nucleotide 3''-phosphodiesterase (CNPase) at various reperfusion endpoints ranging from 30 min up to 28 days. The results showed that activate astrocytes were observed after 30 min and peaked at 3 h to 1 day after reperfusion in ischemic penumbra, and peaked at 7 days of reperfusion in ischemic core. Diabetes inhibited the activation of astrocytes in ischemic hemisphere. Demyelination occurred after 30 min of reperfusion in ischemic core and peaked at 1 day. Diabetes caused more severe demyelination compared with non-diabetic rats. Remyelination started at 7 days and completed at 14 and 28 days in ischemic region. Diabetes inhibited the remyelination processes. It is concluded that ischemia activates astrocytes and induces demyelination. Diabetes inhibits the activation of astrocytes, exacerbates the demyelination and delays the remyelination processes. These may contribute to the detrimental effects of hyperglycemia on ischemic brain damage.     

Protective role of cytosolic NADP(+)-dependent isocitrate dehydrogenase, IDH1, in ischemic pre-conditioned kidney in mice

Ischemic pre-conditioning protects the kidney against subsequent ischemia/reperfusion (I/R). This study investigated the role of cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDH1), a producer of NADPH, in the ischemic pre-conditioning. Mice were pre-conditioned by 30 min of renal ischemia and 8 days of reperfusion. In non-pre-conditioned mice 30 min of ischemia had significantly increased the levels of plasma creatinine, BUN, lipid peroxidation and hydrogen peroxide in kidneys, whereas in pre-conditioned mice, the ischemia did not increase them. The reductions of reduced glutathione and NADPH after I/R were greater in non-pre-conditioned mice than in pre-conditioned mice. Ischemic pre-conditioning prevented the I/R-induced decreases in IDH1 activity and expression, but not in glucose-6-phosphate dehydrogenase activity. In conclusion, protection of the kidney afforded by ischemic pre-conditioning may be associated with increased activity of IDH1 which relates to increased levels of NADPH, increased ratios of GSH/total glutathione, less oxidative stress and less kidney injury induced by subsequent I/R insult.     

Structural changes and hemodynamic relations in the microcirculatory bed of the mesentery of the white rat during the period of sexual maturation

Structural changes and hemodynamic relations have been studied in the microcirculatory bed of the white rat small intestine mesentery during sex maturation (from the 3d up to the 10th week of the postnatal development). All calculations are performed regarding the mesenteric segment limited with two intestinal arteries, which is considered as an elementary microvascular module. Complication of the microcirculatory bed construction takes place at the expense of increasing number (nearly five-fold) of microvessels in the segment and increase of the capillary network density. The hemodynamic factor plays a certain role for stimulating the process of the capillary growth. The definitive structure of the mesenteric microcirculatory bed is completed by the 7th week. The main rearrangement of the microcirculatory system during the developmental process from a simple arterio-venular loop up to a complex microcirculatory bed with a branching capillary network is performed within the limits of the mesenteric segment.     

The blood microcirculatory bed of the tunica muscularis of the human esophagus in postnatal ontogeny]

The analysis of morphological and morphometrical data of the muscular membrane and its blood microcirculatory bed has demonstrated that their development during the postnatal ontogenesis advances unevenly. An intensified growth and development of the muscular membrane morphological structures, including its blood microcirculatory bed occurs from 3 up to 30 years of life. Their maximal growth is noted from 12 up to 30 years of age. The stages of intensified development of the muscular membrane and its blood microcirculatory bed change into stages of retarded growth, where processes of involutive character preponderate. This is especially noticeable from 60 and more years of age. The stages noticed in the muscular membrane development and its blood microcirculatory bed are characterized both by general and topographical morphofunctional peculiarities specific for every stage of organogenesis.     

Photooptical and ultrastructural changes in the microcirculatory bed of the kidney after functional vasoconstriction

In experiments on rats it was found that at the early stages (5 to 15 minutes) after vasoconstriction of the kidney caused by adrenaline solution there occurred sharp narrowing of the intraorganic arterial bed lumen, particularly that of the afferent arterioles. Ultrastructural changes in the glomerular renal capillary components observed were morphological expression of the effect of angiospasm and circulatory hypoxia. Residual phenomena of constriction of the renal microcirculatory bed still persisted at later stages--in 3, 7 days. These changes characterized the stage of peculiar mobility and contractile properties of their endothelial cells, caused by spasmogenic disturbances of microcirculation.     

Role of the kidneys in the pathogenesis of lithium poisoning]

Lithium intoxication was induced in rats by intraperitoneal administration of lithium chloride in a daily dose of 200 mg/kg (0.22 LD50) for 6 days. Polyuria connected with pathological changes in the epithelium of the convoluted tubules and depression of the antidiuretic hormone--acid mucopolysaccharides system in the area of the straight kidney tubules was observed on the 6th day of the experiments. Oligouria and death of some of the animals on the 7th experimental day was caused by severe lesions the kidney structure. Further observation (30 days) demonstrated that, along with the regeneration processes, there developed a marked sclerosing ofthe kidney tissue. A conclusion was drawn that severe lithium intoxication was associated with the development of acute renal insufficiency. Functional reserves of the kidneys after the cessation of lithium chloride administration remained lowered for a long period.