Biomicroscopy was used to study order I-IV branches of the uterine artery in sexually mature female Wistar rats after a single 5- or 10-min direct exposure of the right broad ligament of the uterus ...to a helium-neon laser beam in the red band of the spectrum (λ=632.8 nm, output power 2 mW, intensity 20 mW/cm
2
). Under the influence of laser exposure, there was a significant increase in the diameter of small uterine branches and a weaker increase in large vessels with a well-developed muscular membrane. Preliminary administration of zinc IX protoporphyrin hemoxygenase blocker (30 mmol/kg) reduced reactivity of the vascular bed to laser irradiation, mainly of order I-II branches. It was concluded that carbon monoxide can act as an intermediary between the laser exposure and uterine vessels.
The quantitative content of HIF-1α- and HIF-2α-immunopositive brain neurons in Wistar rats was studied 1, 15, and 30 days after modeling of myocardial infarction. In rats of the control group, the ...immunohistochemical markers HIF-1α and HIF-2α in the prefrontal cortex of the brain were determined in few pale-colored neurons and capillaries. One day after myocardial infarction simulation, the number of HIF-1α
+
neurons increased, and on day 15 it reached the maximum level: the concentration of immunopositive neurons and capillaries increased by 24.7 and 18.4%, respectively, in comparison with the control. After 30 days, the number of HIF-1α
+
structures decreased, but remained above the control values. The number of neurons and capillaries positively stained for HIF-2α peaked only on day 30 of the postinfarction period.
This review presents data on the cellular-molecular mechanisms regulating angiogenesis associated with the vascular endothelium. Existing concepts hold that the control of angiogenesis involves ...activated endothelial cells and their precursors (progenitor cells), which synthesize and release angiogenic molecules with different chemical structures and mechanisms of biological action, but all allowing these cells to control each stage of angiogenesis directly or indirectly. Balanced functioning of the system of molecular stimulators and inhibitors of angiogenesis is particularly important for the brain, as excessive formation of blood vessels, like inadequate development of blood vessels, leads in certain conditions to rapid and irreversible changes in nervous tissue. Post-operative neurorepair cannot occur without adequate reperfusion of the injured part of the brain, which can be supported by timely stimulation of angiogenesis, while intensification of this process in tumors, conversely, has adverse consequences. Tumor growth and metastasis are significantly linked with increases in the level of vascularization of malignant tissue, while blockade of angiogenesis is not infrequently the only productive method of limiting tumor growth. However, we have insufficient knowledge of the mechanisms regulating angiogenesis in the brain at the cellular-molecular level in physiological conditions and pathology, so angiogenic influences do not always produce the expected effect.
The capillaries containing MMP-2 and its tissue inhibitor TIMP-2 were examined in cerebral cortex and white matter obtained from intact Wistar rats (
n
=5) and the rats with progressing experimental ...renovascular hypertension (
n
=35). In hypertensive rats, the changes in intensity of the immunohistochemical reaction and in the density of capillaries expressing TIMP-2 significantly differed from the corresponding values in MMP-2-positive capillaries, which resulted in pronounced deviation of MMP-2/TIMP-2 index from the control level (especially in cerebral cortex) probably attesting to enhanced risk of complications in cases with arterial hypertension.
First-fourth order pial branches of the median cerebral artery were studied by biomicroscopy in male Wistar rats aged 1 and 12 months. Irrespective of age, CO-mediated mechanisms are involved in the ...regulation of the basal tone of pial vessels of various diameters (more so of arteries with well-developed muscular tunic). Injection of hemin confirmed that endogenous production of CO maintained vasodilatation and this effect was most pronounced in large pial branches of young animals, while zinc protoporphyrin IX blocked this effect in all cases. On the other hand, zinc IX protoporphyrin did not modify NO-mediated reaction caused by injection of L-arginine, while hemin compensated (though not completely) vasoconstriction induced by NO synthase blocker L-NAME. In contrast to NO, the effect of CO on blood vessels was not so rapid and potent, but more lasting. Other targets for CO were arteries with well-developed muscular tunic, while targets for NO were small vessels. The vasomotor effects of both gas transmitters were more pronounced in young animals.
Using the biomicroscopy method, we studied the reaction of arterial and venous vessels of the broad ligament of the uterus in outbred female rats to irradiation with helium-neon laser (λ=632.8 nm; ...power output 2 mW). Small arteries were found to be most sensitive to laser irradiation. The veins of the broad ligament of the uterus demonstrated lower reactivity to laser irradiation of the same duration than arterial vessels, which can be explained by morphological, functional, and hemodynamic differences.
The locations of heme oxygenase-2 (HO-2) and heme oxygenase-1 (HO-1) in the walls of 1st- to 4th-order arterial branches in the pia mater were studied in normotensive rats and in animals with induced ...renovascular hypertension (RVH). Immunohistochemical detection of heme oxygenase was performed on 40 Wistar rats. The vasomotor function of carbon monoxide (CO) in 3rd- to 5th-order arteries was found to be associated mainly with the endothelium, while in 1st- and 2nd-order arteries it was associated with myocytes. In normotensive animals, HO-2 was involved in forming CO, while both HO-2 and HO-1 had roles in hypertensive animals. The largest number of vessels expressing HO-1 was seen in week 16 of RVH, when the proportion of vessels positive for HO-2 was minimal, which is consistent with the time at which arterial pressure stabilizes at the new, higher, level.
Structural organization of the microcirculatory bed and mast cells in the uterus of mature female Wistar rats (
n
=60) were examined every 2 h over 24 h. During night hours, many vessels ...characterized by intensive reaction to NADPH-diaphorase and endothelial NO synthase were detected in the endometrium, and the density of these vessels and mast cells was quite high. During the day and evening hours, the capillaries with high levels of enzymes involved in NO synthesis and mast cells were less numerous. NO directly regulating the diameter of arteries and the intensity of transcapillary exchange can act as a signal molecule in the temporal dynamics of the vasoceptive action of estrogens and their receptors in the uterus.
First to fourth-order branches of the uterine artery in sexually mature female Wistar rats were studied by biomicroscopy. After administration of a CO donor hemin (60 mM), the diameters of large ...uterine branches with a well-developed muscle layer markedly increased, while the increase in diameter of small vessels with one often interrupted layer of smooth muscle cells increased insignificantly. Zinc protoporphyrin IX (30 mM) in all cases blocked this effect. However, zinc protoporphyrin IX does not affect NO-mediated reaction of the branches of the uterine artery caused by administration of L-arginine (60 mM), and L-NAME did not significantly affect reactivity of uterine artery branches associated with the hemoxygenase—CO system. In contrast to NO, CO produced less potent and rapid, but more sustained effect. The target for the hemoxygenase—CO system is mainly arteries with developed muscular layer, while the target for the NO synthase—NO is small vessels where endothelium plays a Rdecisive role in the regulation of vasomotor reactions.
The distribution of two enzymes involved in the formation of carbon monoxide, heme oxygenases 1 and 2, in the pial branches of orders I-V of the middle cerebral artery basin and in intracerebral ...vessels was studied in adult Wistar rats. Immunohistochemical studies detected hemeoxygenase-2 in the endothelium of the small pial and intracerebral arterioles and in myocytes of pial branches I-III. Heme oxygenase 1, an inducible form of the enzyme, is normally not expressed in the cerebral vessels, but the enzyme is expressed in response to sodium metaarsenite. In this case, heme oxygenase markers are detected in myocytes of pial arteries I-II and in the endothelium of small pial and intracerebral vessels. Sodium meta-arsenite is inessential for immunolocation and quantitative distribution of heme oxygenase 2 in the vessels.
