The effect of chromium on rat insulinoma cells in high glucose conditions.
OBJECTIVE
it has been suggested that Chromium (Cr), one of the essential minerals, can be beneficial to type 2 diabetic patients because it lowers blood glucose levels by improving various steps in insulin action. A few studies reported that Cr might also have some beneficial effects in people with type 1 diabetes mellitus and in streptozotocin-treated rats, but direct beneficial effects of Cr on pancreatic beta cells have not been proven. We performed this study to determine whether Cr could have direct protective effects on INS-1 cells in high glucose conditions that mimic the actual diabetic state.


METHODS
INS-1 cells were cultured for 48h in RPMI medium with 33mM glucose as the stress condition and 11mM glucose as a control. CrCl(3) was used to verify whether Cr could protect INS-1 cells from glucotoxic stress. Cell viability and apoptosis were evaluated by MTT assay and FACS. The level of insulin mRNA, by semi-quantitative RT-PCR, was significantly reduced at 33mM glucose concentration after 48h of incubation.


RESULTS
cell viability was reduced by 50%, and 35% of the cells underwent apoptosis at the same culture condition. Addition of various concentrations of CrCl(3) to INS-1 cells in 33mM glucose for different durations of time did not reveal any beneficial effects on cell viability, degree of apoptosis, insulin mRNA levels, and glucose stimulated insulin secretion.


CONCLUSIONS
we could not find any evidence that Cr had direct beneficial effects on INS-1 cells in high glucose induced stress conditions.
Kwon
Min J
MJ
Paik Diabetes Center, Department of Internal Medicine, College of Medicine, Inje University, 633-165 Gaegum-Dong, Pusanjin-Gu, Busan, 614-735, South Korea.
Chung
Hye S
HS
Yoon
Chang S
CS
Ko
Jung H
JH
Jun
Hae J
HJ
Kim
Tae K
TK
Lee
Soon H
SH
Ko
Kyung S
KS
Rhee
Byung D
BD
Kim
Mi K
MK
Park
Jeong H
JH
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival; D002712:Chlorides / Q000378:metabolism*; D002857:Chromium / Q000378:metabolism*; D017608:Chromium Compounds / Q000378:metabolism*; D019610:Cytoprotection; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005786:Gene Expression Regulation; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000235:genetics / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000166:cytology* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats
D002712:Chlorides; D017608:Chromium Compounds; D007328:Insulin; D012333:RNA, Messenger; D002857:Chromium; C017133:chromous chloride; D005947:Glucose