Mechanical Stretch and 17β-Estradiol Regulate HspB1 (Hsp27) Expression in the Rat Myometrium.
Bibliographic record
Abstract
Despite many medical advances and increases in knowledge, the underlying mechanisms that regulating uterine contractions during labour are still poorly understood. It also remains a major cost on healthcare to deal with the many problems that occur as a result of pre-term labour. HspB1, also referred to as Hsp27, is a stress protein that plays an important role in actin-myosin interaction and is significantly upregulated in myometrium during late pregnancy and labour. Thus it may be considered a contraction associated protein (CAP). We previously examined the role of progesterone and uterine distension, with a unilaterally pregnant rat model, on HspB1 expression during pregnancy. The objective of the present study was to investigate the effects of 17β-Estradiol, and further investigate the effect of mechanical stretch, on expression of HspB1. To delve further into the effect of mechanical stretch, we again used the unilaterally pregnant rat model in combination with extra small laminaria tents (cervical dilators). These dilators were surgically inserted in non-gravid horns of pregnant rats (day 18) to achieve a dynamic stretch of the myometrium (24hrs duration) and mimic the stretch exhibited in the gravid horn. HspB1 expression was increased in the laminaria containing horns compared to non-gravid horns and approached expression levels found in the gravid horns. We further investigated the effect of stretch through a non-pregnant, ovariectomized rat model. Laminaria tents were inserted into one uterine horn, while the other served as a control. This dynamic stretch induced HspB1 expression compared to the control horn. To investigate the role of 17β-Estradiol on HspB1 expression, non-pregnant ovariectomized rats were injected with exogenous 17β-Estradiol (5ug), or vehicle, and myometrial samples were taken at regular intervals thereafter. 17β-Estradiol treatment markedly increased HspB1 expression, compared to vehicle controls, peaking shortly after injection and returning to baseline by the following day. These experiments help show that both endocrine signals and mechanical stretch play an important role in regulating HspB1 expression. Our work also reinforces the hypothesis that HspB1 is an important molecule for myometrial contraction, and as such should be considered during any future development of tocolytic strategies. Research supported by the Natural Sciences and Engineering Research Council.
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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".