Peculiarities of neoplasms , appeared after total body irradiation and homeostasis parameters in rats.

Background: Tissue damage and disruption of metabolic processes as a result of total body irradiation (TBI) could lead to tumorigenesis.
Methods: 25 from 32 rats were total body X- irradiated  with sublethal dosage per rat - 6 Gy. On month 12±1 ,19 of  irradiated animals had visually detectable tumors. In this period all rats were sacrificed. The alkaline phosphatase (ALP) ; alanine aminotransferase (ALT), aspartate aminotransferase (AST),  amylase , lactate dehydrogenase (LDH) ; Ca 2+ ; creatinine ; glucose ; phosphorus ; urea  ; uric acid , total protein, pO2, pCO2, pH, blood cell level  were measured in blood. Tumors were isolated, measured and histologically examinated. Accordingly the ratio ( C1) of tumor weight   to lactate level in blood   in tumor bearing rats, the animals  were  divided on 3 conditional groupings K1-K3 with C1<0.5; C1 >0.5<1.5; C1> 1.5.
Results: About a year after TBI (12±1 months) 76% of female rats had visually detected tumors, which were histologically classified as benign fibro adenomas. Metabolic disorders and hematological changes observed during this period indicate disturbances in the homeostasis system. The blood lactate level in all tumor-bearing animals was statistically higher than in control (healthy) rats; a typical phenomenon for neoplasm growth. In the majority of animals with neoplasms (63%), the tumor weight and the levels of lactate and lactate dehydrogenase (LDH) in the blood were in direct relation (coefficient = tumor weight / lactate level >0.5<1.5) and histological analysis revealed the signs of biphasic hyperplasia of glandular lobes and connective tissue stroma, associated with secretory and proliferative activities in tumor.  In the conditional grouping of animals with relatively high values of coefficient (≥1.5), neoplasms were represented by fibrous and glandular tissues presenting a predominant stromal fibrous component, associated with the prevalence of high proliferation in tumor. While in the rat conditional grouping (20% of animals) with a relatively low coefficient (< 0.5) an epithelial structure with homogeneous basophilic content predominated in the glandular lumens, suggesting the domination of high secretory activity in tumor.
Conclusions:  Total body irradiation promoted the alterations of hematological and biochemical parameters of homeostasis in rats and provoked the appearance of benign tumors one year after. Coefficient C – the  ratio of tumor mass  to lactate or LDH value in blood seems to be an informative indicator of the histological peculiarities of tumor, suggesting  the prevalence of proliferative  or secretory activity , or the balance between proliferative and secretory activities of tumor cells.