Introduction. Despite considerable informativeness, factor analysis in biomedical research is still rarely used. Therefore, we set out to introduce our colleagues to the theoretical foundations of factor analysis and to demonstrate its application in our own material.
Material and methods. The study subjects were 58 healthy female Wistar rats 240-290 g, 10 of which were intact and the others were subjected to water-salt loading for 6 days.The day after the completion of the drinking course in all rats, at first, a sample of peripheral blood was taken for leukocytogram analysis. Then they assessed the state of autonomous regulation by the parameters of the HRV. Animals were then placed in individual chambers for collecting daily urine. The experiment was completed by decapitation of rats in order to collect as much blood as possible.The plasma levels of the hormones of adaptation were determined: corticosterone, triiodothyronine and testosterone as well as electrolytes: calcium, magnesium, phosphates, chloride, sodium and potassium (both in plasma and in erythrocytes); nitric metabolites: creatinine, urea, uric acid, medium molecular polypeptides, bilirubin; lipid peroxidation products: diene conjugates and malonic dyaldehide, antioxidant enzymes: superoxide dismutase erythrocytes and catalase plasma, as well as amylase and glucose. Most of the listed parameters of metabolism were also determined in daily urine. In addition, the osmolarity of the urine was measured. According to the parameters of electrolyte exchange, hormonal activity was evaluated: parathyroid, calcitonin and mineralocorticoid.In the blood, the parameters of immunity were determined according to the tests of the 1st and 2nd levels of the WHO. The spleen, thymus and adrenal glands were removed. Immune organs weighed and made smears-imprints for counting splenocytogram and thymocytogram. For them, as well as leukocytogram, Shannon’s entropy was calculated. In the adrenal glands after weighing, the thickness of glomerular, fascicular and reticular zones was measured. Factor analysis (principal component method) was implemented with the program Statistica 5.5.
Results. It was found that the dispersion of the information field of 106 parameters of the neuro-endocrine-immune complex and metabolism is absorbed by 20 principal component (PCs). Using the Cattel method, the number of PCs analyzed is limited to twelve, the total contribution of which to the total variance of the raw data is 66,2%, ie, it reaches the required critical level (2/3).
We have found that there is a general pattern – the combination of neuro-endocrine and immune parameters in 8 individual PCs, which, in our material, illustrates the correctness of the concept of a triple neuroendocrine-immune complex, the elements of which carry out bilateral interaction. On the other hand, in 10 PCs, neuro-endocrine and/or immune parameters are combined with metabolism parameters. The cause/effect relationships between them will be the subject of a subsequent study.
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