Aim of the study. To explore the structural and functional changes of neurons, glial cells, and synaptic terminals in layers I, III, and V of the sensorimotor cortex (SMC) of the rat brain after bilateral common carotid artery ligation (CCAL).Material and methods. Incomplete cerebral ischemia was simulated by irreversible bilateral CCAL (2-vessel model of global ischemia without hypotension) on white rats (n=36). Comparative evaluation of the studied SMC structures was performed in the control group (intact rats, n=6) on days 1, 3, 7, 14, and 30 (n=30) after CCAL. Nissl, hematoxylin-eosin staining, and immunohistochemical reactions for NSE, MAP-2, p38, GFAP, and IBA1 were used. Numerical density of pyramidal neurons, astrocytes, oligodendrocytes, microglial cells, and relative area of p38-positive material (synaptic terminals) were determined. Statistical hypotheses were tested using nonparametric methods with Statistica 8.0 software.Results. After CCAL, the number of degenerative neurons in rat brain SMCs increased. The peak of numerical density of unshrunken neurons was detected after day 1. Later, the numerical density of hyperchromic unshrunken neurons decreased, while that of shrunken neurons increased. These parameters did not reach the control values. The changes in SMC neurons were accompanied by an increase in the numerical density of microglial cells after day 1 and its subsequent decrease. Immunohistochemistry for IBA1 revealed signs of microglial cell activation such as change in shape and loss of processes. Maximum increase in the SMC density of oligodendrocytes was observed on day 7, and that of astrocytes on day 14 after CCAL. The maximum number of NSE-positive neurons occurred on day 1 after CCAL. There was a significant decrease in the number of NSEpositive neurons in SMC layer III on days 3, 7, and 14, and an increase in the number of NSE-positive neurons on day 30. The number of NSE-positive neurons in layer V of the SMC progressively decreased throughout the whole study period. The evolution of changes in the proportion of p38-positive material (synaptic terminal area) differed significantly between the layers of SMC. In the layers I and III, this parameter first decreased (days 1 and 3) and then increased (days 7, 14, and 30). In layer V of SMC, the activation of the protein expression was observed in the acute phase (days 1 and 3), then it decreased on days 7 and 14, and increased again on day 30. The changes found in the numerical density of neurons, glial cells and synaptic terminals were associated with dehydration and overhydration of SMC. We found strong to medium significant associations between the relative area of terminals and neuropil swelling and edema zones.Conclusion. After CCAL, layers I, III, and V of the SMC of white rats revealed destructive and compensatory changes in neurons, glial cells, and inter-neuronal communication structures. Taken together, all these changes indicate a significant layer-by-layer variability of the neural tissue response to CCAL. Layer III (secondary projection complex) of the SMC was affected to a greater extent. Reorganization of neuronal-glial and interneuronal interrelations occurred along with a prominent neuropil overhydration.

Exposure to xylene, at low concentrations (less than 50 mg / m3) under the conditions of its production, from petroleum raw materials was characterized in the first 3 years of work by the development of hematopoietic irritation in working people, as well as an increase in the functional activity of leukocytes. 5 years after the start of work under these conditions, the above indicators approached the data of the control group, and then there was a decrease in the functional usefulness of leukocytes.

Workers in the conditions of modern oil refineries are exposed to a complex of chemicals and intensive industrial noise. The most constant components of chemical compounds are the ultimate, unsaturated and aromatic hydrocarbons, determined in most cases at a level much lower than the MPC. Under the action of low-intensity factors, the peripheral blood picture can serve as a significant indicator.