acetyl-aspartyl-glutamyl-valyl-aspartal and Disease-Models--Animal

Retinitis pigmentosa(RP) is a human disease characterized by loss of photoreceptor cells, especially rods, leading to visual disturbance and eventually to blindness. Effective treatment for RP control is still unavailable. The establishment of reliable animal models is essential for a better understanding of this disease, and for the development of therapeutic intervention. Here we summarize the establishment of N-methyl-N-nitrosourea (MNU)-induced retinal degeneration in animals, and success in disease control using this model.. Retinal damage induced by MNU was highly reproducible and involved photoreceptor cell loss. It was obvious in all animals at approximately 7 days following a single systemic administration of MNU to adult mice (60 mg/kg), rats (60-75 mg/kg), hamsters (90 mg/kg), shrews (65 mg/kg), and monkeys (40 mg/kg). Extensive investigation in the rats revealed that MNU-induced photoreceptor cell loss was due to apoptosis with a decrease of Bcl-2 protein, increase of Bax protein, and activation of caspase families. Therapeutic to control MNU-induced photoreceptor cell loss in rats was evaluated with caspase-3 inhibitor (Ac-DEVD-CHO), nicotinamide(NAM), and docosahexaenoic acid(DHA); 4,000ng Ac-DEVD-CHO injected intravitreally 0 and 10 h after MNU suppressed disease progression, 25-1,000 mg/kg NAM subcutaneously injected concurrently or subsequently to MNU reversed retinal damage, and dietary supplementation of 9.5% DHA counteracted photoreceptor cell loss.. Although the mechanisms triggering pathogenesis and the apoptotic cascade may differ between animals and humans, MNU-induced retinal degeneration is caused by photoreceptor cell apoptosis. Thus, suppression of MNU-induced photoreceptor cell apoptosis in animals may provide therapeutic information for RP control in humans.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Caspases; Cricetinae; Disease Models, Animal; Docosahexaenoic Acids; Humans; Methylnitrosourea; Mice; Niacinamide; Oligopeptides; Photoreceptor Cells; Proto-Oncogene Proteins c-bcl-2; Rats; Retinal Degeneration; Retinitis Pigmentosa

Cultures derived from the cerebral cortices and hippocampi of 17-day-old mouse fetuses infected with the CVS strain of rabies virus showed loss of trypan blue exclusion, morphological apoptotic features, and activated caspase 3 expression, indicating apoptosis. The NMDA (N-methyl-D-aspartate acid) antagonists ketamine (125 microM) and MK-801 (60 microM) were found to have no significant neuroprotective effect on CVS-infected neurons, while the caspase inhibitor Ac-Asp-Glu-Val aspartic acid aldehyde (25 microM) exerted a marked neuroprotective effect. Glutamate-stimulated increases in levels of intracellular calcium were reduced in CVS-infected hippocampal neurons. Ketamine (120 mg/kg of body weight/day intraperitoneally) given to CVS-infected adult mice produced no beneficial effects. We have found no supportive evidence that excitotoxicity plays an important role in rabies virus infection.

Topics: Animals; Apoptosis; Caspase 3; Caspase Inhibitors; Cells, Cultured; Cysteine Proteinase Inhibitors; Disease Models, Animal; Excitatory Amino Acid Antagonists; Ketamine; Mice; N-Methylaspartate; Neurons; Oligopeptides; Rabies; Rabies virus

In the present study we assessed the neuroprotective effects of the pan-caspase inhibitor z-VAD.fmk [N-benzyloxycarbony-valine-alanine-aspartate-(OMe)-fluoromethylketone], and the caspase-3 inhibitor Ac-DEVD.CHO (acetyl-aspartate-chloromethylketone) in the double-lesion rat model of striatonigral degeneration (SND), the core pathology underlying levodopa-unresponsive parkinsonism associated with multiple system atrophy (MSA). Male Wistar rats were divided into three groups, receiving either Ac-DEVD.CHO, z-VAD.fmk or normal saline before lesion surgery, comprising a sequential unilateral quinolinic acid (QA) lesion of the striatum followed by a 6-hydroxydopamine (6-OHDA) lesion of the ipsilateral medial forebrain bundle. At 2 weeks post lesion, all rats underwent testing of spontaneous nocturnal locomotor behavior in an automated Photobeam Activity System (FlexField). Immunohistochemistry was performed with tyrosine hydroxylase, dopamine and cyclic adenosine 3',5'-monophosphate-regulated phosphoprotein and glial fibrillary acidic protein antibodies. Morphometry was performed using computerized image analysis. Behavioral and morphological analysis failed to show striatal or nigral protection in caspase inhibitor-treated animals. Our findings suggest that anti-apoptotic strategies are unrewarding in the SND rat model and, therefore, alternative neuroprotective interventions such as anti-glutamatergic agents or inhibitors of microglial activation should be explored instead.

Topics: Amino Acid Chloromethyl Ketones; Analysis of Variance; Animals; Basal Ganglia; Behavior, Animal; Caspase Inhibitors; Cell Count; Cell Size; Disease Models, Animal; Dopamine and cAMP-Regulated Phosphoprotein 32; Functional Laterality; Immunohistochemistry; Male; Motor Activity; Multiple System Atrophy; Nerve Tissue Proteins; Neurons; Neuroprotective Agents; Oligopeptides; Oxidopamine; Phosphoproteins; Quinolinic Acid; Rats; Rats, Wistar; Tyrosine 3-Monooxygenase

Previous studies from our laboratory have demonstrated that Bcl-2 has a proapoptotic effect on neocarzinostatin (NCS)-treated PC12 pheochromocytoma cells. In the present study, we examine the mechanisms of this effect and demonstrate its relevance for the in vivo situation. Four hours after NCS treatment, a 23-kDa cleavage product of Bcl-2 was detected in whole cell lysates of bcl-2-transfected PC12 cells. In contrast, bcl-2 transfection protected PC12 cells from cisplatin-induced apoptosis, and cisplatin treatment did not result in Bcl-2 cleavage. Similarly, Bcl-2 cleavage did not occur and Bcl-2-mediated protection from, rather than potentiation of apoptosis was observed after NCS treatment of MCF-7 breast cancer cells. The caspase 3-specific inhibitor Ac-DEVD-CHO prevented Bcl-2 cleavage and attenuated NCS-induced apoptosis in bcl-2-transfected PC12 cells, whereas it had no effect on NCS-induced apoptosis in mock-transfected PC12 cells. Furthermore, MCF-7 cells do not express caspase 3, a finding in concert with the lack of Bcl-2 cleavage in this line. In in vivo experiments, xenografts of bcl-2-transfected PC12 cells were more susceptible to NCS toxicity than were xenografts of mock-transfected PC12 cells. Caspase 3-mediated Bcl-2 cleavage therefore plays an important role in the potentiation by Bcl-2 of NCS-induced apoptosis.

Topics: Animals; Antineoplastic Agents; Apoptosis; Caspase 3; Caspase Inhibitors; Caspases; Cisplatin; Cysteine Proteinase Inhibitors; Disease Models, Animal; Drug Interactions; Drug Screening Assays, Antitumor; Humans; Mice; Mice, Nude; Oligopeptides; PC12 Cells; Proto-Oncogene Proteins c-bcl-2; Rats; Transfection; Tumor Cells, Cultured; Xenograft Model Antitumor Assays; Zinostatin