P-005 Could early life stress be related to the hippo signaling pathway in rat testis?
Authors: İnanç İ , Baysal E , Erdemli E 
Published: July 2024

Abstract

Study question
Is there a change in the Hippo signaling pathway in the rat testis exposed to early life stress for 14 days in the postnatal period?

Summary answer
It was observed that the YAP and p-YAP signaling levels decreased in rats exposed to early-life stress when compared to the control groups.

What is known already
Hippo signaling pathway has been reported that it participates in many events such as cell division, proliferation, differentiation, and programmed cell death. YAP (Yes-Associated Protein) and p-YAP (phospho-YAP) are the main components of this pathway. Deterioration in sperm production and decreasing the serum testosterone levels were observed in rats exposed to stress stimulation in literature. However, the molecular mechanisms underlying these problems in the male reproductive system caused by stress have not yet been elucidated.

Study design, size, duration
180-minute maternal deprivation and isolation model was applied to the early-life stress group (ELS) every day between the 1st and 14th postnatal day. Tail blood was collected before and after stress conditions on 14th postnatal day. Serum corticosterone levels were detected. On the 14th day, the control and ELS groups were sacrificed and the testicles were placed in appropriate fixatives.

Participants/materials, setting, methods
In total of 10 newborn Wistar albino male rats were used. Two groups were formed as Control (n = 5) and ELS (n = 5) groups. On postnatal 14th day, the groups were sacrificed. For immunohistochemical analyses, testis were taken into buffered formalin, paraffin blocks were made and the sections were taken. ELISA kit was used for serum corticosterone level.

Main results and the role of chance
The post-stress serum corticosterone levels of the ELS group were found to be significantly higher compared to the control group (p &lt; 0.05). At least 60 seminiferous tubules were evaluated for immunohistochemical analyzes in the testis. H-score evaluation was applied. It was determined that YAP and p-YAP expressions decreased in the ELS group when compared to control group (p &lt; 0.05) on the 14th postnatal day when mitosis and proliferation are high in testis cell groups. In addition the seminiferous tubule diameter was smaller in the experimental group. As we conducted in the literature research, stress conditions were generally based on adult subjects. There are insufficient data on the effects of stress on the testis in the early postnatal periods. This suggests that stress created in the early period may cause various defects as the cells enter the adult period.

Limitations, reasons for caution
This study was performed in vivo rat model in the postnatal 14th days. In further studies, groups including the adulthood period will be added.

Wider implications of the findings
After the 14th day of the postnatal period day, the blood-testis barrier is formed and spermatogenesis processes begin. Any defect that occurs in this day can cause problems in sperm development. This study can bring a new perspective to researching the effects of stress on testis in prepubertal period.

Trial registration number
not applicable