Aim. Measure of the histological changes in neurons in the parietal cortex and hippocampus of rats with partial, subtotal, stepwise subtotal, and total cerebral ischemia. Material and Methods. Studies were performed on 84 rats. Partial cerebral ischemia was modelled by ligation of one common carotid artery. Subtotal cerebral ischemia was modelled by ligation of both common carotid arteries. Stepwise subtotal cerebral ischemia was performed by sequential ligation of both common carotid artery with 7-day, 3-day or 1-day intervals. Total cerebral ischemia (CI) was modelled by decapitation. Results. When comparing the morphological changes of neurons in the parietal cortex and hippocampus, we observed that, with the aggravation of the severity of cerebral ischemia, there was a progressive increase in the number of hyperchromic shrivelled neurons and neurons with pericellular oedema. Modelling of more severe types of ischemic damage lead to pronounced morphological changes in neurons – a decrease in size, deformation of the perikaryon, and increase in the degree of neuronal chromatophilia with their wrinkling. Conclusions. The smallest morphological changes in neurons were noted in the partial cerebral ischemia groups and subgroup 1 of stepwise subtotal cerebral ischemia, with an interval between common carotid artery dressings of 7 days. The most obvious morphological changes were observed in the conditions of total cerebral ischemia after 1 day. Changes in the parietal cortex and hippocampus were unidirectional, but in the parietal cortex, which is most sensitive to oxygen deficiency, they were more pronounced.

Objective: Evaluation of changes in the content of ATP synthase in the parietal cortex and hippocampus of the brain of rats with ischemia of varying severity in a comparative aspect. Methods:The experiments were performed on 88 male outbred white rats weighing 260 ± 20 g. Brain ischemia was modeled under conditions of intravenous thiopental anesthesia (40-50 mg / kg). Total cerebral ischemia was modeled by decapitation of animals. The brain sampling was carried out 1 hour and 24 hours after decapitation -to study tissue respiration of mitochondria, as well as 1 hour later to determine the content of ATP synthase. Subtotal cerebral ischemia was modeled by simultaneous ligation of both common carotid arteries. The material was taken after 1 hour to determine the content of ATP synthase. Stepwise subtotal cerebral ischemia was performed by sequential ligation of both common carotid arteries with an interval of 7 days. The sampling was carried out 1 hour after ligation of the second common carotid artery in each of the subgroups. Partial cerebral ischemia was modeled by ligation of one common carotid artery on the right. The sampling was carried out 1 hour after the operation. Determination of the content of ATP synthase was carried out by immunohistochemical method using monoclonal antibodies. For this purpose, after decapitation, the brain was quickly removed from the rats, pieces of the cerebral cortex were fixed in zinc-ethanolformaldehyde at + 4 ° C (overnight), then embedded in paraffin. Results:In the group of stepwise subtotal cerebral ischemia, the smallest decrease in the content of ATP synthase was observed in the 1 st subgroup with an interval between dressings of 7 days, while the greatest decrease in the content of the enzyme was noted in the 3 rd subgroup with the minimum interval between the dressings of the common carotid artery (1 day). Modeling of more severe types of ischemic damage led to pronounced morphological changes in neurons in the parietal cortex and hippocampus of the rat brain -a decrease in their size, deformation of the perikarya, an increase in the degree of neuronal chromatophilia with their simultaneous wrinkling and subsequent death. These disorders were most pronounced in the 3 rd subgroup of stepwise subtotal

To study the parameters of respiration of mitochondria of rat brain homogenates with its total and subtotal ischemia. Methods:The studies used models of total and subtotal cerebral ischemia. Cerebral ischemia was modeled under conditions of intravenous thiopental anesthesia (40-50mg/kg). Total cerebral ischemia was modeled by decapitation of animals. Subtotal cerebral ischemia was modeled by simultaneous ligation of both common carotid arteries. The sampling of material for the study of tissue respiration of mitochondria was carried out 1 hour and 24 hours after decapitation or ligation. To study mitochondrial respiration, the brain was removed in the cold (0-4°C), dried with filter paper, weighed and homogenized in an isolation medium containing 0.32 M sucrose, 10 mM Tris-HCl, 1 mM EDTA, pH 7.4 (in the ratio 1:10) using a Potter-Evelheim homogenizer with a Teflon pestle according to the modified method.Results: An increase in V1 and V2 and a decrease in the phosphorylation coefficient (ADP/O) indicates proton transfer bypassing the ATP synthase complex. Enzymes of the mitochondrial matrix and cytochrome in this model of cerebral ischemia do not yet have pronounced damage, as evidenced by the high rates of V1 and V2. More pronounced disturbances with the use of succinate than with the use of malate/ glutamate indicate a greater damage to the succinate dehydrogenase complex of the electron transport chain, as in the case of total cerebral ischemia. Conclusion:The most pronounced decrease in the respiration indices of the mitochondrial fraction of brain homogenates occurs in total cerebral ischemia due to the complete cessation of the blood supply to the brain neurons. With this method of modeling cerebral ischemia, the appearance of hyperchromic shriveled neurons with pericellular edema is characteristic.

Introduction. Cerebral ischaemia leads to the development of numerous morphofunctional disorders of the cerebral cortex, which can be exacerbated by the introduction of a Nω-nitro-L-arginine methyl ester (L-NAME), which is a non-selective inhibitor of nitric oxide synthase (NOS). Aim. To study the morphological features of rat brain neurons in subtotal ischaemia during the administration of L-NAME and naturally occurring omega-3 polyunsaturated docosahexaenoic acid (DHA). Material and Methods. Subtotal cerebral ischaemia was modelled in rats by ligation of both common carotid arteries. L-NAME and DHA were given individually or in combination to separate groups of rats. L-NAME (5 mg/kg) was administered intramuscularly immediately before ligation and DHA (5 mg/kg) intragastrically during the week before ligation. Results. The introduction of DHA alone had a corrective effect on the hippocampus under conditions of subtotal ischaemia, reducing the number of shadow cells and hyperchromic wrinkled neurons, without significantly affecting the size and shape of the neurons of the parietal cortex. However, the previous administration of DHA to rats with cerebral ischaemia receiving a NOS inhibitor did not abrogate the negative effects on the state of the neurons in the cerebral cortex. Conclusion. The administration of DHA can modulate the morphological disorder of the hippocampus which occurs in subtotal cerebral ischaemia.

No abstract