Changes in the nuclei of dying neurons as studied with thymidine autoradiography

Abstract

Thymidine autoradiography has been used at light and electron microscopic levels to elucidate intracellular events during the death in chick embryos of isthmo-optic neurons deprived of trophic maintenance from their axonal target organ, the retina. When the intense cytoplasmic vacuolization described in the accompanying paper (Hornung, Koppel, and Clarke, J. Comp. Neurol. 283:425-437, '89) was beginning, the nuclei also underwent profound changes. They became more electron dense and shrank; their membranes became more sharply defined and convoluted; they sometimes contained pyknotic balls, but apparently only in the early stages of cell death; all lost more than half of their content of DNA, some of which was transferred to the largest kind of cytoplasmic vacuole. This transfer may have involved the budding off of nuclear regions containing pyknotic balls. The cells continued to survive for a day or 2 after these severe losses of nuclear DNA, sustaining intense endocytic activity. Pronounced unscheduled DNA synthesis occurred in the nuclei, but this was insufficient to replace the lost DNA.

Apoptosis of spinal interneurons induced by sciatic nerve axotomy in the neonatal rat is counteracted by nerve growth factor and ciliary neurotrophic factor

“…In this sense, chromatin compactness and degeneration of the nuclear envelope were frequently observed in the neurons undergoing apoptosis. Also, nuclear alterations, such as chromatin compactation and, in some cases, contact between nuclear and cytoplasm contents were observed, as previously described by Clarke and Hornung (1989) and Clarke (1990). Events related to chromatolysis, e.g., migration of the nucleus to the periphery and Nissl substance dissolution, were observed in our analysis, in accordance to the classical descriptions (Peters et al, 1991).…”

Characterization of the phenotype and birthdates of pyknotic dead cells in the nervous system by a combination of DNA staining and immunohistochemistry for 5'-bromodeoxyuridine and neural antigens.

“…BrdU immunostaining not only permits identification of birthdates of particular cell populations (Soriano and Del Rio, 1991;Del Rio and Soriano, 1989;Miller and Nowakowski, 1988) but also allows the period of death of such populations to be determined because of their higher microscopic resolution. A recent study suggests that degenerate dying cells can incorporate small amounts of [3H]-thymidine during their degenerative phase (Clarke and Hornung, 1989). The possibility that the BrdU-positive pyknotic cells detected in the present study may have been labeled by similar mechanisms can be ruled out, since BrdU was administered at least 1 week before immunostaining, and BrdU is available for incorporation into DNA only during a short period of time after a given pulse injection.…”

Persistence of early-generated neurons in the rodent subplate: assessment of cell death in neocortex during the early postnatal period

“…In our studies of interstitial (subplate) cells in the temporal cortex of kittens Fatal-Valverde, 1987, 1988) we described neuronal cell death in electron microscope images as previously recognized (Pilar and Landmesser, 1976;Chu-Wang and Oppenheim, 1978;Cunningham, 1982;Clarke and Hornung, 1989;Clarke, 1990;Johnson and Deckwerth, 1993). From these studies a generalization emerged: neuronal death was considered a universal feature for subplate cells (see review in Allendoerfer and Shatz, 1994).…”