Effects of Age and Long-Term Ovariectomy on the Estrogen-Receptor Containing Subpopulations of Beta-Endorphin-Immunoreactive Neurons in the Arcuate Nucleus of Female C57BL/6J Mice
Notice bibliographique
Résumé
We have reported a decrease in the number of arcuate nucleus (ARC)-immunoreactive β-endorphin neurons in old (24 months) female C57BL/6J mice versus young (5 months) mice. Here, we have tested by immunocytochemistry whether age-related changes in β-endorphin neuron numbers are selective for β-endorphin neurons which do or do not contain estrogen receptors (E2R). We also compared β-endorphin neuron number in mice with short- (S) and long-duration (L) ovariectomy (OVX), since the latter may protect against neuroendocrine aging. Mice were studied at 5 (young), 12 (middle-aged), or 23-24 months (old). When the mean number of neurons per tissue section (15 sections per animal) was examined, there were no significant differences between young and middle-aged S-OVX females for either β-endorphin, E<sub>2</sub>R, or β-endorphin/ E<sub>2</sub>R neuron number. However, there were significant decreases in β-endorphin-containing neurons in the oldest age group versus young females (young S-OVX: 74.4 ± 11 (±SD) immunopositive neurons per tissue section, n = 10 mice; young L-OVX: 61.6 ± 6.9, n = 6; old S-OVX: 45.7 ± 9.9, n = 7; and old L-OVX: 37.5 ± 7.3, n = 7). There were also decreases in β-endorphin neurons which contained E<sub>2</sub>R in the oldest animals (young S-OVX: 16.6 ± 6.4; young L-OVX: 13.7 ± 1.3; old S-OVX: 9.2 ± 1.8; L-OVX: 6.0 ± 1.5) (p < 0.05 ANOVA). Both age (p < 0.001, two-way ANOVA) and ovarian status (p < 0.05) independently affected neuron number for both the β-endorphin and β-endorphin E<sub>2</sub>R populations versus young mice. We tested whether the observed age and/or ovarian-related decreases were proportionally greater in the subpopulation of β-endorphin neurons which contained E<sub>2</sub>R compared to the total β-endorphin neuron population. In the oldest age group, there was no significant difference in the decrease with age in the population of β-endorphin neurons which contained E<sub>2</sub>R and the total β-endorphin population (p = 0.208). When we examined the E<sub>2</sub>R neuron population as compared to the β-endorphin neuron populations, age-related decreases in the β-endorphin neuronal population tended to be greater than the decreases seen in the E<sub>2</sub>R neuron population (p = 0.054 repeated measures ANOVA). The tyrosine hydroxylase (TH) neuron population was studied to test whether there were changes in another ARC neuron population. There was no age-related change in either TH neuron number (young S-OVX: 35.8 ± 6.2, n = 4; middle-aged S-OVX: 33.1 ± 2.8, n = 4; old S-OVX: 33.4 ± 3.4, n = 4) or in the number of TH neurons which contained E<sub>2</sub>R (young S-OVX: 7.6 ± 1.0; middle-aged S-OVX: 7.2 ± 0.8; old S-OVX: 6.9 ± 1.2). These data demonstrate that ARC β-endorphin-containing perikarya are sensitive to alterations associated both with age and ovarian status; these effects are independent of one another. Our findings fail to support the hypothesis that L-OVX has a protective effect on hypothalamic neurons in older females. The subpopulation of β-endorphin neurons that contain E<sub>2</sub>R are not affected to any greater degree by age or ovarian status than the β-endorphin neuron population as a whole in the old animal.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».