Activation of the caspase cascade underlies the rat trigeminal primary neuronal apoptosis induced by neonatal capsaicin administration
| Autor: | H.W. Jin, Kazuo Mukae, Tomoichiro Yamaai, T. Sugimoto, Kayo Nomura, Hiroyuki Ichikawa, Ryuji Terayama |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Male
medicine.medical_specialty Histology Injections Subcutaneous Sensory system Apoptosis DNA Fragmentation Rats Sprague-Dawley chemistry.chemical_compound Subcutaneous injection Trigeminal ganglion Internal medicine medicine In Situ Nick-End Labeling Animals Caspase Neurons TUNEL assay biology Caspase 3 Caspase 9 Rats Enzyme Activation Endocrinology chemistry Animals Newborn Trigeminal Ganglion Capsaicin Anesthesia biology.protein Systemic administration DNA fragmentation Female |
| Zdroj: | Archives of histology and cytology. 68(4) |
| ISSN: | 0914-9465 |
| Popis: | The systemic administration of capsaicin is known to cause a massive loss of sensory primary neurons in newborn rats. Here we examined the trigeminal ganglion neurons immunohistochemically for the possible induction of activated forms of caspases-9 and -3 following a subcutaneous injection of capsaicin in newborn rats. The DNA fragmentation signal was labeled by a TUNEL method. TUNEL-positive neurons were rare (< 0.5%) at 24 h after injection of the vehicle without capsaicin. After the capsaicin injection, TUNEL-positive neurons began to increase by 12 h, reached a peak at 24 h (11.4%), and returned to the control level by 120 h. Vehicle control levels of caspase- 9-immunoreactive (ir) and caspase-3-ir neurons were low (< 0.5%). Neonatal capsaicin administration induced caspase-9-immunoreactivity (ir) and -3-ir. The temporal distributions of caspase-9-ir and caspase-3-ir neurons were similar to those of TUNEL-positive neurons with peak expressions at 24 h of 13.2 and 11.1%, respectively. A double-stain analysis at 24 h post-injection indicated 72% of TUNEL-positive neurons were caspase-9-ir, and 70% caspase-3-ir. Conversely, 78 and 68% of caspase-9-ir and caspase-3-ir neurons, respectively, were TUNEL-positive. Comparison of two adjacent sections immunostained for the two different antigens revealed the co-expression of the two caspases. These results suggest that neonatal capsaicin triggers the caspase cascade and, thereby, induces trigeminal primary neuronal apoptosis. |
| Databáze: | OpenAIRE |
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