Antioxidative properties of human milk and spermine are not related to expression of Hsp 70.
OBJECTIVE
Heat shock proteins (Hsps) have been detected in various tissues, including those in the intestines, and play a role in cellular protection. Polyamines, such as spermine (SPM), are found in human milk (HM) and act as antioxidants. We hypothesized that the antioxidative property of SPM is related to the expression of Hsp and examined this relationship in an intestinal epithelial cell (IEC) line.


METHODS
(i) Confluent IEC-6 cells were exposed to mild heat shock (43 degrees C, 1 h) and then allowed to recover at 37 degrees C for 24 h. Hydrogen peroxide (H(2)O(2)) was applied to induce oxidative stress and cell viability was evaluated. (ii) Cells were exposed to mild heat shock or pre-incubated with HM or pre-incubated with 5 microM SPM for 24 h. Hsp70 expression in IEC-6 cells was analysed by Western blot.


RESULTS
The survival rate of cells treated with mild heat shock after H(2)O(2) challenge was significantly higher than that of non-pretreated cells. Western blot analysis demonstrated that Hsp70 was expressed in IEC-6 cells treated with mild heat shock but not in IEC-6 cells pre-incubated with HM or 5 microM SPM.


CONCLUSIONS
Mild heat shock treatment induces Hsp70, which acts as an antioxidant in IEC-6 cells, but HM or SPM does not induce Hsp70 in this system.
Shoji
Hiromichi
H
Department of Pediatrics, Juntendo University School of Medicine, Tokyo, Japan. hiromichi.shoji@nifty.ne.jp
Shimizu
Toshiaki
T
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D018929:Cell Culture Techniques; D002460:Cell Line; D002470:Cell Survival; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis*; D018869:Heat-Shock Response / Q000502:physiology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D008895:Milk, Human / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D051381:Rats; D013096:Spermine / Q000378:metabolism*
D000975:Antioxidants; D018840:HSP70 Heat-Shock Proteins; D016877:Oxidants; D013096:Spermine; D006861:Hydrogen Peroxide