Beneficial effects of oligopeptides from marine salmon skin in a rat model of type 2 diabetes.
OBJECTIVE
This study aimed at investigating whether treatment with oligopeptides from marine salmon skin (OMSS) could modulate type 2 diabetes mellitus (T2DM)-related hyperglycemia and β-cell apoptosis in rats induced by high fat diet and low doses of streptozotocin and its therapeutic mechanisms.


METHODS
Groups of T2DM rats were treated with OMSS or bovine serum albumin (3.0 g/kg/d) for 4 wk and their blood samples, together with those of normal control rats, were collected before and 4 wk after treatment. The levels of fasting blood glucose (FBG) and insulin, serum superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH), tumor necrosis factor-alpha (TNFα), and interferon-gamma (IFNγ) in rats were determined. The islet cell apoptosis and Fas/FasL expression were detected by TUNEL and immunohistochemistry.


RESULTS
In comparison with control rats, higher levels of FBG and frequency of apoptotic islet cells were detected in the bovine serum albumin group of diabetic rats, accompanied by higher levels of Fas expression in the pancreatic islets, serum TNFα, IFNγ, and MDA, but lower levels of SOD and GSH. However, the levels of FBG and frequency of apoptotic islet cells were significantly reduced in OMSS-treated rats. Lower levels of Fas expression were observed in the pancreatic islets of OMSS-treated rats. Significantly reduced levels of serum TNFα, IFNγ, and MDA, but increased levels of SOD and GSH, were detected in OMSS-treated rats.


CONCLUSIONS
Treatment with OMSS significantly reduced FBG in diabetic rats. This antidiabetic activity may be mediated by down-regulating T2DM-related oxidative stress and inflammation, protecting the pancreatic β-cells from apoptosis.
Zhu
Cui-Feng
CF
Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing, PR China.
Peng
Hong-Bing
HB
Liu
Gui-Qin
GQ
Zhang
Fan
F
Li
Yong
Y
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D001786:Blood Glucose / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy*; D004041:Dietary Fats / Q000009:adverse effects; D005978:Glutathione / Q000097:blood; D006943:Hyperglycemia / Q000188:drug therapy; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D007371:Interferon-gamma / Q000097:blood; D007515:Islets of Langerhans / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D009842:Oligopeptides / Q000494:pharmacology / Q000627:therapeutic use*; D018384:Oxidative Stress / Q000187:drug effects; D011492:Protein Hydrolysates / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012474:Salmon; D012709:Serum Albumin; D013311:Streptozocin / Q000008:administration & dosage; D013482:Superoxide Dismutase / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D019014:fas Receptor / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D000975:Antioxidants; D001786:Blood Glucose; D004041:Dietary Fats; C491898:Fas protein, rat; D007004:Hypoglycemic Agents; D009842:Oligopeptides; D011492:Protein Hydrolysates; D012709:Serum Albumin; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D008315:Malondialdehyde; D013311:Streptozocin; D007371:Interferon-gamma; D013482:Superoxide Dismutase; D005978:Glutathione