Histological, Histochemical and Biochemical Changes in the Liver, Kidney, Lung and Spleen under the Effect of Repetitive Hyperthermia in Rat Neonates

Background: Artificial hyperthermia in association with radiotherapy or chemotherapy has become a promising method for cancer treatment. Thus, this study was designed to assess the impact of repetitive hyperthermia (41˚ ± 0.5˚C) on some normal histological, histochemical, and biochemical variables in newborn rats.

Materials and methods: After parturition, the neonates were randomly chosen and assigned to two groups (each being comprised of ten animals): one group was exposed to hyperthermia (41˚ ± 0.5˚C) and the other one was exposed to normothermia (25˚ ± 0.5˚C). Both groups were treated daily for 2 hours from the day of labor until the age of 21 days.

Results: Histological and histochemical examination of the tissue sections of hypothermic rat neonates exhibited numerous cirrhotic changes in liver with deposition of collagen fibers extending from the central veins or portal tracts forming thick or thin fibrotic septa and even pseudolobule formations. The kidneys showed areas of necrosis, edema, glomerular hyperplasia or infiltration of inflammatory cells, marked amounts of collagen surrounding some Malpigian corpuscles and in between the renal tubules in a focal or diffuse fashion. The lungs revealed alveolar haemorrhage, focal fibrosis, emphysema of the alveoli with rupture of some alveolar walls and hyperplasia of the cells lining alveoli with collagen distribution in the peribronchiolar area as well as in the tunica adventitia of the peribronchiolar dilated blood vessels, and in the interalveolar and perialveolar areas. The spleen suffered from severe hyperemia in the red pulps and sinusoids with distorted lymphoid nodules and atrophy of others. The quantitative measurement of the degree of fibrosis proved a significant (p < 0. 01) accumulation of collagen fibers in all the examined tissues except for spleen. Additionally, hyperthermia caused a significant increase in most measured serum biochemical variables (ALT, AST, GGT, LDH, total bilirubin, total protein, albumin, creatinine & urea) except for the globulin content whose concentration showed a significant decrease.

Conclusion: As high preferential absorption ability of tumour tissue components to heat over normal tissues rely, in part, upon their higher collagen and protein content, attention should be paid to the repetitive effect of high temperature on the architecture of normal tissues, total collagen and protein contents in addition to its upshots on certain biochemical indices to appraise the impact of the method on patients particularly newborns and those with multi-recurrences carcinoma.