Change in morphology and oxytocin receptor expression in the uterine blood vessels during the involution process.
BACKGROUND
The histological changes in uterine blood vessels during pregnancy have been well investigated, but there have been few reports focusing on the changes in blood vessels during the involution process, especially within the first 24 h. We observed the process of uterine involution, focusing on the vessels of the resected uterus.


METHODS
Paraffin-embedded uterine samples from 15 patients who underwent hysterectomy because of severe cervical laceration and uterine rupture were examined. The time between delivery and hysterectomy ranged from 15 min to 456 h. The specimens were stained with hematoxylin-eosin, elastica-van Gieson and an antioxytocin receptor antibody.


RESULTS
Changes in the uterine vessels varied substantially based on their location. The intima in arteries of the endometrial side thickened within 5 h after delivery. On the serosal side, phlebosclerosis was demonstrated 6 weeks postpartum. Immunoreactivity for the oxytocin receptor (OTR) appeared in the muscular medias of arteries 5 h after delivery although it was not expressed before this period.


CONCLUSIONS
Remodeling of uterine vessels involved thickening of the arterial intima and OTR expression in vessel walls during the first 5 h postpartum; the parameters normalized within 6 weeks. However, phlebosclerosis persisted for a long time on the serosal side.
Wakasa
Tomoko
T
Department of Diagnostic Pathology, Osaka City University Graduate School of Medicine, Osaka, Japan.
Wakasa
Kenichi
K
Nakayama
Masahiro
M
Kuwae
Yuko
Y
Matsuoka
Keiko
K
Takeuchi
Makoto
M
Suehara
Noriyuki
N
Kimura
Tadashi
T
D000328:Adult; D001158:Arteries / Q000378:metabolism* / Q000473:pathology*; D001707:Biopsy, Needle; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000009:adverse effects / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007044:Hysterectomy / Q000379:methods; D007150:Immunohistochemistry; D007744:Obstetric Labor Complications / Q000473:pathology*; D006473:Postpartum Hemorrhage / Q000473:pathology / Q000601:surgery; D011247:Pregnancy; D018045:Receptors, Oxytocin / Q000378:metabolism*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D019687:Uterine Inversion / Q000473:pathology*; D014599:Uterus / Q000098:blood supply* / Q000473:pathology*
D018045:Receptors, Oxytocin