Impact of Pregnancy and Glucocorticoid Treatment on NF-κB and MUC5AC in Mucosa of Rat Larynx

Cellular and Molecular Effects of Steroid Sex Hormones on the Vocal Folds: A Scoping Review

OBJECTIVE

Steroid sex hormones (SSH) target cell nuclei to affect transcription. Although laryngeal tissue is theorized to be hormonally responsive, SSH receptor presence and cellular effects on the vocal folds are not well-established. A scoping review of this literature might inform future research.

DATA SOURCES

Medline, Embase, Scopus, and Web of Science were searched.

REVIEW METHODS

This review followed JBI and PRISMA-ScR Guidelines. Two independent reviewers screened each title/abstract and full text according to eligibility criteria. Exclusion criteria included primary outcomes based on subjective interpretation and secondary effects on the vocal folds (e.g., voice).

RESULTS

Three hundred and sixty one articles were screened at the title/abstract level, 83 at the full-text level, and 32 met inclusion criteria. Fourteen studies were performed in humans and 15 in animals; 3 were review articles. In studies directly examining receptors (n = 17), estrogen receptors (ER) were found in 10 of 15 studies, progesterone receptors (PR) in 6/10, and androgen receptors (AR) in 6/9. When the effects of SSH on vocal folds were studied (n = 16), estrogen had effects in 10/13, progesterone in 3/3, and androgens in 4/5. ER and PR were mostly identified in epithelium and fibroblasts of lamina propria (LP) while AR was found in muscle, lamina propria, and epithelium.

CONCLUSIONS

Existing evidence variably supports the presence of SSH receptors in vocal fold tissue; therefore, further clarification is needed. Estrogen and progesterone were most identified in mucosal tissue, where they decrease fibrosis and help maintain the epithelial barrier. Androgens appear to be pro-fibrotic in epithelium and hypertrophic in muscle. Laryngoscope, 135:540-554, 2025.

Methodological Approaches for Vocal Folds Experiments in Laryngology: A Scoping Review

OBJECTIVE

The aim of this study was to describe the methodological approaches adopted in experimental researches in laryngology intervention studies.

METHODS

The study was performed as a scoping review using the electronic databases Medline (PubMed), Web of Science, Embase, BioMed Central and SCOPUS. These databases were manually searched from 1995 (or its inception) until the most recently published articles in June 2022. The inclusion criteria were as follows: a) studies performed with animal models in voice and/or larynx therapy, intervention and/or surgery; b) studies with participant populations composed with animals; c) studies containing original research; d) studies performed with at least one objective measurement for treatment and or intervention; e) studies reporting at least one method of larynx intervention; and f) publications written in English, Spanish or Portuguese. The exclusion criteria were as follows: a) studies considering without any objective intervention and or treatment; b) studies without animal models; and c) studies that reviewed articles or books. These criteria were set to increase inter-study comparability.

RESULTS

There were found 26 studies that showed that in experimental laryngology. There were retrieved four main characteristics in the retrieved studies. It was observed five major groups of experimental models used for assessing vocal folds: dog (38.5%), rat/mouse (23,1%), pig (23.1%), rabbit (19.2%), human (11.5%), and sheep (3.8%). In addition, three characteristics were observed: sample (up to 20 subjects 88.5%), type of surgery/intervention (100%) and duration (up to 30 days 61.5%).

CONCLUSION

In experimental laryngology, the state of the art is grounded on mainly in dog, rat and pig in vocal folds assessment. Up to 20 subjects, surgery/intervention and experimental trial lasting no more than 30 days are frequent methodological approaches in this research field.

Expression of nuclear factor kappa B in ovine maternal inguinal lymph nodes during early pregnancy

BACKGROUND

Pregnancy-induced immunological changes contribute to the maternal immune tolerance. Nuclear factor kappa B (NF-κB) pathway participates in regulating both innate and adaptive immunities, and lymph nodes play key roles in adaptive immune reaction. However, it is unclear whether early pregnancy changes the expression of NF-κB family in maternal lymph node in sheep.

METHODS

In this study, the samples of inguinal lymph nodes were collected from ewes on day 16 of the estrous cycle, and on days 13, 16 and 25 of pregnancy, and expression of NF-κB family, including NF-κB p105 (NFKB1), NF-κB p100 (NFKB2), p65 (RELA), RelB (RELB) and c-Rel (REL), were analyzed through real-time quantitative PCR, Western blot and immunohistochemical analysis.

RESULTS

The expression levels of NF-κB p105 and c-Rel downregulated, but NF-κB p100 upregulated on day 25 of pregnancy. The expression levels of p65, RelB and c-Rel peaked at day 13 of pregnancy, and expression level of RelB was higher during early pregnancy comparing to day 16 of the estrous cycle. In addition, p65 protein was located in the subcapsular sinus and lymph sinuses.

CONCLUSION

This paper reported for the first time that early pregnancy has effects on the expression of NF-κB family, which may contribute to the maternal immunoregulation through blood circulation and lymph circulation during early pregnancy in sheep.

Biological and Acoustic Sex Differences in Rat Ultrasonic Vocalization

The rat model is a useful tool for understanding peripheral and central mechanisms of laryngeal biology. Rats produce ultrasonic vocalizations (USVs) that have communicative intent and are altered by experimental conditions such as social environment, stress, diet, drugs, age, and neurological diseases, validating the rat model's utility for studying communication and related deficits. Sex differences are apparent in both the rat larynx and USV acoustics and are differentially affected by experimental conditions. Therefore, the purpose of this review paper is to highlight the known sex differences in rat USV production, acoustics, and laryngeal biology detailed in the literature across the lifespan.

Impact of pregnancy on voice: a prospective observational study

PURPOSE

We aimed to assess if there is a significant change in voice of pregnant women by the end of third trimester.

MATERIALS AND METHODS

Forty-nine pregnant women were enrolled in this study between April 2019 and March 2020. Subjective and objective voice evaluation was conducted in the third trimester and three months after delivery. The Turkish version of the VHI-10 questionnaire was filled out by every participant. GRBAS scale was used for perceptual voice evaluation. Acoustic analyses were conducted by Multi-Dimensional Voice Program (MDVP) (Computerized Speech Lab, Kay Elemetrics Corporation, Lincoln Park, NJ). Fundamental frequency (fo), Jitter percent (Jitt), Shimmer percent (Shim), noise to harmonic ratio (NHR), maximum phonation time (MPT), voice turbulence index (VTI), vocal intensity, and scale parameters were categorized as predelivery (a) and postdelivery (b).

RESULTS

Comparison of acoustic parameters of the third trimester with the third month postpartum revealed statistically significant increases for fo (p = .013), MPT (p = .008), and vocal intensity (p≤.001) as well as a significant decrease for VTI (p≤ .001). No statistically significant difference was found for NHR, Jitt, and Shim. Comparison of both VHI-10 and GRBAS scores revealed statistically significant decreases.

CONCLUSIONS

Disturbances in certain vocal parameters suggest that vocal abnormalities observed during pregnancy are mainly due to anatomical alterations of the lower respiratory system. It would be appropriate to warn pregnant women about bad vocal habits and vocal hygiene. In addition, it would be appropriate to recommend professional voice support to pregnant women who use their voices intensively due to their profession.

Role of VPAC1 anD VPAC2 receptors in the etiology of pregnancy rhinitis: an experimental study in rats

Introduction

Pregnancy rhinitis is a common sex hormone-related otorhinolaryngological disorder. There are some epidemiological and physiological studies on pregnancy rhinitis, but histopathological and biomolecular changes have not been studied thoroughly.

Objectives

The receptors VPAC1 and VPAC2 are known for their roles in allergic rhinitis. On the other hand, activation of subclinical allergy has been suggested in the pathophysiology of pregnancy rhinitis. Therefore, we aimed to compare the physiological and gestational pattern of VPAC1 and VPAC2 expression in rat nasal mucosa.

Methods

Twenty adult Wister albino female rats were enrolled into the study. Two groups constituted as 10 control (group A) and 10 pregnant (group B) rats. They were fed ad libitum and sheltered at room temperature (22°±2 °C). The rats were sacrificed at the 20th day of gestation by intraperitoneal injection of 400 mg/kg Na-pentobarbitone. Then, 10 − 15 mL of blood was taken, and samples were reserved for the detection of serum estradiol and progesterone levels by ELISA test. The nasal septum was resected and divided in half for immunohistochemical analyses and real time polymerase chain reaction testing of VPAC1 and VPAC2.

Results

VPAC1 and VPAC2 were found to be in all layers of septal specimens, but the immunostaining of surface epithelium was more distinct in specimens of both groups. We demonstrated higher overall staining intensity in the pregnant group. PCR revealed significant increase in expression of VPAC1 (p = 0.023) and VPAC2 (p = 0.021) in pregnant group when compared with control group. In addition, we demonstrated upregulatory effect of estradiol and progesterone on the vasoactive intestinal peptide receptor expression.

Conclusions

Gestational up-regulation of nasal VPAC1 and VPAC2 was shown both by PCR and immunohistochemical analysis. These findings support the hypothesis that PR is caused by the activation of subclinical allergy that is present before pregnancy.

The Role of TREK-1 and AQP5 in Gonadocorticoid-Related Voice Disorders

OBJECTIVES

TWIK-related potassium channel-1 (TREK-1) and Aquaporin 5 (AQP5) are involved in epithelial integrity and fluid transport, respectively. In this study, we aimed to compare physiological and gestational patterns of TREK-1 and AQP5 location and expression in rat larynx. Our secondary objective was to reveal the effect of estradiol (E2) and progesterone (PG) on these two biomolecules.

METHODS

This study was conducted on 20 Wister albino female rats which were assigned as control (group A) and pregnant group (group B). The rats were sacrificed at 20th day of pregnancy. Blood was obtained directly from the ventricle for detection of serum E2 and PG levels. Larynx was resected for immunohistochemical analyses and real-time polymerase chain reaction testing for detection of TREK-1 and AQP5 staining and expression, respectively.

RESULTS

Relative TREK-1 (P = 0.035) and AQP5 (P = 0.019) expression was found to be significantly high in group B when compared with group A. We found positive correlation between serum E2 levels and both biomolecules (TREK-1; P = 0.018, AQP5; P = 0.016). We also found positive correlation between serum PG levels and both biomolecules (TREK-1; P = 0.001, AQP5; P = 0.019). TREK-1 immunostaining was found to be higher in surface epithelium and lamina propria of vocal cord mucosa. AQP5 was particularly found to be located in basement membrane and adjacent superficial lamina propria. We revealed the physiological and gestational pattern of laryngeal TREK-1 and AQP5 expression for the first time. Gestational expression of both TREK-1 and AQP5 was found to be increased. Stimulatory effect of E2 and PG on laryngeal TREK-1 and AQP5 expression was also revealed.

CONCLUSIONS

We revealed upregulatory effect of E2 and PG on laryngeal TREK-1 and AQP5 expression. Based on this finding, it can be suggested that TREK-1 and AQP5 play role in biomolecular processes leading gonadocorticoid-related voice changes.