Influence of timing (pre-puberty or skeletal maturity) of ovariohysterectomy on mRNA levels in corneal tissues of female rabbits.
Bibliographic record
Abstract
PURPOSE: Corneal thickness and curvature are reported to be influenced by hormonal changes associated with menstrual cycle, pregnancy, or menopause. However, the molecular mechanisms leading to these alterations are not clearly understood. The present study focuses on gene expression patterns (mRNA levels) in corneal tissues following surgically induced menopause in an animal model. The impact of lower hormone levels on mRNA levels in corneal tissues after pre-puberty ovariohysterectomy (OVX) was compared to that in skeletally mature adult animals. METHODS: Skeletally mature adult female rabbits were either left unoperated (control) or were subjected to OVX at 54 weeks of age using an approved protocol. The central (approximately 6 mm) and the peripheral corneal tissues were harvested from normal and OVX rabbits eight weeks after surgery. In a second study, young sexually immature rabbits at eight weeks of age were subjected to OVX and corneal tissues were collected when the animals were 22 and 32 weeks of age. In both experiments, RNA was isolated from corneal tissues and RT-PCR was used to assess mRNA levels for several relevant molecules. RESULTS: When mature animals were examined eight weeks after OVX, mRNA levels for molecules such as the estrogen receptor, decorin, collagen I, collagen V, and several growth factors were found to be significantly decreased in central corneal tissues. Interestingly, no corresponding changes in mRNA levels were observed for these same molecules in peripheral corneal tissues. When young, pre-pubertal animals were subjected to OVX, mRNA levels were found to be mainly unchanged for the OVX animals at 22 weeks of age i.e., after 14 weeks of low hormone conditions. However, significant decreases in mRNA levels for a similar subset of molecules were observed when the animals were at least 32 weeks of age, i.e., after 24 weeks of a low hormone environment. Examination of peripheral corneal tissues did not show significant changes in mRNA levels due to OVX at either 22 or 32 weeks of age except for collagens I and V at 32 weeks of age. CONCLUSIONS: These results indicate significant alterations in mRNA levels in the central corneal tissues of rabbits following OVX. Interestingly, peripheral corneal tissues show very little alteration in mRNA levels for the same molecules. Furthermore, OVX had a more rapid impact on mRNA levels in mature animals than in skeletally immature animals. Thus, loss of hormone producing tissues during growth and maturation apparently delayed the impact of hormone removal compared to loss after maturity had been attained and growth stimuli are likely absent. Therefore, specific areas of the cornea are more responsive to hormone levels than others. The impact of the loss of hormones is influenced by the maturation state of the rabbit, but mRNA levels for a similar subset of genes are affected by OVX in both age groups.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".