THE USE OF TEXTURE ANALYSIS TO STUDY THE TIME-COURSE OF CHROMATOLYSIS

Image analysis of the textural feature entropy of the Nissl substance was used to monitor the time course of chromatolysis in regenerating h ypoglossal motoneurons and degenerating facial motoneurons 4-112 days after hypoglossal-facial anastomosis in rats. Changes in the Nissl sub stance were detected that were not obvious on the basis of subjective judgement of the light-microscopical appearance of the neurons. Chroma tolysis started 4 days post operation (dpo) and was not reversed at 11 2 dpo in both nuclei. The increase of chromatolysis was 14-28 dpo fast er in the regenerating hypoglossal neurons than in degenerating facial neurons. Maximal chromatolysis was measured at 56-70 dpo in both nucl ei. Afterwards chromatolysis persisted at a significantly higher level in the degenerating facial motoneuron pool. In conclusion, chromatoly sis is a very long persisting reaction. In the beginning chromatolysis is faster and greater in regenerating rather than in degenerating neu rons. In contrast, passing the maximal reaction, chromatolysis is main tained at a higher level in degenerating motoneurons. Image analysis o f textural features is a suitable and reliable tool to monitor the tim e course of neuronal cell body changes. The presented quantitative met hod could be applied in any neurobiological study influencing the rege neration or degeneration of motoneurons. (C) 1997 Elsevier Science B.V .