Heat shock proteins (HSP)-60, -70, -90, and 105 display variable spatial and temporal immunolocalization patterns in the involuting rat uterus
Liman, Narin
Uterine involution involves substantial tissue destruction and subsequent repair and remodelling, with similarities to the microenvironments present during wound healing. Although involution is a physiologically normal process, it may generate a stressful microenvironment for the uterine cells, and thus it can induce the expression of heat shock proteins (HSPs), which were originally identified as stress-responsive proteins. The aim of this study was to determine the spatial and temporal expression and localization of four heat shock proteins (HSPD1/HSP60, HSPA/HSP70, HSPC/HSP90 and HSPH1/HSP105/110) in the involuting rat uterus using immunohistochemistry. The HSPs were expressed in the luminal (LE) and glandular epithelium (GE), fibroblasts, mast cells, myometrial myocytes, perimetrial mesothelium and blood vessels, and each of the uterine tissues had distinctive patterns of HSP immunostaining. HSPD1/HSP60 was located in the cytoplasm, often with the granular appearance that is typical of organellar localization, whereas HSPA/HSP70, HSPC/HSP90 and HSPH1/HSP105 were located in the nucleus and cytoplasm. The immunolocalization patterns of all HSPs in the LE showed alterations that accompanied involution, but no difference was observed in the other uterine cells. HSPs were localized in the apical and basal cytoplasm of the LE on postpartum days 1, 5 and 10, but only in the apical cytoplasm on day 3. Furthermore, on day 3, HSPA/HSP70, HSPC/HSP90 and HSPH1/HSP105 immunostaining in the crypts and GE were stronger than those in the LE, whereas on day 10, the nuclear HSP90 immunoreaction was stronger in the LE than in the GE. These observations suggest that HSPs may be involved in many physiological processes, such as cell cycle control, cell proliferation, regulation of cell death and survival, and differentiation during the involution process.(AU)
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