Cytophotometry of nucleic acids and morphometry of motor neurons and oligodendroglia in the spinal cord of rats treated with CCNU (lomustine).

CCNU, a nitrosourea derivative, is a potent agent used in cancer chemotherapy and effective also in therapy of brain tumors. This cytostatic is considered to be free of neurotoxic effects. To establish the influence of CCNU on the central nervous system, the drug was administered in oil suspension, intragastrically, to adult rats. The animals received four doses of the drug in 7 days intervals, including three doses of 2.5 mg and the fourth of 5.0 mg. On the 7th day after the last dose experimental rats were sacrificed, their spinal cord removed, fixed in Baker's solution and embedded in paraffin. The sections were stained according to Einarson and subjected to Feulgen reaction for morphometric, karyometric and cytophotometric studies. The measurements of motor neurons and oligodendroglia from anterior horns of the cervical, thoracic and lumbar spinal cord were performed with scanning microscope "Morphoquant" coupled to the KSR 4100 computer. CCNU administration lead to morphometric, karyometric and cytophotometric changes in examined cells. The karyometric and cytophotometric changes were statistically significant and more extensive than morphometric changes which were insignificant. Furthermore, CCNU caused a statistically significant decrease of DNA content in motor neurons and oligodendrocytes in all examined parts of the spinal cord.