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Ocular hypertension is a symptom of a glaucomatous condition characterized by a severe vision decrease. Blindness caused by the apoptotic death of the retinal ganglion cells and of the astrocytes of the optic nerve may eventually result. Experimental hypertension was induced by inoculation of methylcellulose in the anterior chamber. Chromatin staining, TUNEL assay, and inter-nucleosomal DNA fragmentation observed in retina and optic nerve strongly suggest that hypertension causes apoptosis. Immunolocalization of the fibrillary acidic glial protein, specific of cell stress, and caspase-3 in the same tissues, further support this mode of cell death. Activation of the ubiquitin dependent proteolytic system was also observed. Protection from apoptosis exerted by administration of the peroxide scavenger trolox, suggests that the apoptotic pathway is activated by an oxidative stress. The data presented here show that the experimental hypertensive insult induces degenerative and apoptotic events comparable to those observed in human glaucoma.

Neem oil is a natural product obtained from the seeds of the tree Azadirachta indica. Its composition is very complex and the oil exhibits a number of biological activities. The most studied component is the terpenoid azadirachtin which is used for its insecticidal and putative antimicrobial properties. In this report we investigate the biological activity of partially purified components of the oil obtained from A. indica. We show that the semi-purified fractions have moderate to strong cytotoxicity. However, this is not attributable to azadirachtin but to other active compounds present in the mixture. Each fraction was further purified by appropriate extraction procedures and we observed a differential cytotoxicity in the various sub-fractions. This led us to investigate the mode of cell death. After treatment with the oil fractions we observed positivity to TUNEL staining and extensive internucleosomal DNA degradation both indicating apoptotic death. The anti-proliferative properties of the neem oil-derived compounds were also assayed by evaluation of the nuclear PCNA levels (Proliferating Cell Nuclear Antigen). PCNA is significantly reduced in cells treated with a specific fraction of neem oil. Finally, our results strongly suggest a possible involvement of the mitochondrial pathway in the apoptotic death.

We investigated early alterations in rat neurons after experimental ischemic stress. Transient ischemia was generated by bilateral occlusion of the carotids after hypoxia. Data show a relevant increase of the nuclear level of ubiquitin 2 h post-stress as evaluated by immuno-cytolocalization. Ubiquitin returns to normal levels after 6 h. The increase in ischemic/hypoxic rats was localized preferentially in nuclei of hippocampal neurons, although some augmentation was also shown essentially in dendrites. The activation of ubiquitin system is related to a defective homeostasis and might trigger different degenerative processes. With respect to this, we observed chromatin alterations by densitometric analysis. The shown extensive DNA degeneration is consistent with the occurrence of necrotic phenomena at an early stage. However the parallel internucleosomal specific DNA fragmentation, strongly suggests that apoptotic events also occur. In any case both necrosis and apoptosis are likely to occur at same time, although apoptosis is less extensive, and the two phenomena take place in different neural cells.

Experimental administration of di-(2-ethylexyl)-phthalate (DEHP), a plasticiser employed in the fabrication of polyvinyl chloride (PVC), causes increases in lipid metabolising enzymes along with marked peroxisomal proliferation. The effects are found in several mammalian tissues, of which the rodent liver is the most responsive target. Leakage of DEHP from PVC devices is favoured by high temperature and contact with lipid-containing biological fluids. Since preterm babies are currently ventilated through endotracheal PVC tubes, it seemed worthwhile to investigate DEHP effects on immature mammalian lung. In this research, female rats were fed with DEHP in the last week of pregnancy and after delivery, and lungs were excised from 2-day-old pups. At this age, in fact, rat lung histological features closely resemble those found in 24- to 36-week-old human fetuses. In treated animals, morphometric analysis of histological parameters revealed a dramatic decrease in the number of parenchymal airspaces, together with significant increases in their mean size. Moreover, cytochemical detection of the peroxisomal marker catalase revealed an increase in the number of type II pneumocytes. Our findings closely resemble abnormal histological features observed in autoptic lung specimens from children affected with chronic lung diseases.