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Updated: Jun 25, 2026

Measurements of Physiological Stress Responses in C. Elegans
Published on: May 21, 2020
Differential regulation of hepatic heme oxygenase-1 protein with aging and heat stress
Steven A Bloomer1, Hannah J Zhang, Kyle E Brown
1Department of Integrative Physiology, 532 FH, University of Iowa, Iowa City, IA 52242, USA.
Abstract:
Increased expression of heme oxygenase-1 (HO-1) in response to physiological stress is considered to be a protective response, which may be altered with aging. In this study, HO-1 expression was assessed following heat stress by immunoblotting of liver homogenates and isolated hepatocytes from young (6 months) and old (24 months) Fischer 344 rats and by immunohistochemistry. Livers of old rats showed higher baseline levels of HO-1, which was predominately localized to Kupffer cells. After heat stress, young animals showed a greater relative increase in hepatic HO-1, part of which was caused by increased numbers of nonparenchymal cells that were immunoreactive to HO-1. Consistent with these data, HO-1 was significantly upregulated after hyperthermia in vitro only in hepatocytes from young rats. Hence, aging alters stress-induced expression of HO-1 in a cell-specific manner, which may contribute to the diminished stress tolerance observed in older organisms.
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