Title: Expression of phosphatidylinositol-3-kinase, serine/threonine-protein kinase 2 and nuclear transcription factor-kappa B in skeletal muscle of ovariectomized diabetic rats
Abstract: Objective
To investigate the expression of phosphatidylinositol-3-kinase (PI3K), serine/threonine-protein kinase 2(Akt2) and nuclear transcription factor- κB (NF-κB) in skeletal muscle of ovariectomized diabetic rats.
Methods
Twenty-nine female Wistar rats were randomly divided into 3 groups: control group (NS group, n=9), diabetic group (DS group, n=10) and diabetic ovariectomized group (DOVX group, n=10). Rats in NS group were fed with a normal diet, while rats in DS and DOVX groups were fed with a high-carbohydrate/fat diet for 8 weeks and then were given an intraperitoneal injection of streptozotocin (STZ, 30 mg/kg). One week later, rats in DOVX group underwent ovariectomy, while rats in NS and DS groups were subjected to a sham operation, which was similar to ovariectomy except that only a small portion of abdominal fat was removed. Before and after ovariectomy, rats in each group were weighed, and fasting blood glucose, fasting plasma insulin were measured. At 12 weeks after the ovariectomy, the expression of PI3K, Akt2 and NF-κB in skeletal muscle of the rats was measured by immunohistochemistry and RT-PCR.
Results
(1) The mRNA levels of PI3K (0.797±0.043) and Akt2 (0.753±0.076) in DS group were lower than the mRNA levels of PI3K (0.870±0.051) and Akt2 (0.844±0.013) in NS group (t=2.722, 3.368, respectively, both P<0.05), but higher than DOVX group (0.715±0.068, 0.666±0.038, and t=2.686, 2.526, respectively, both P<0.05). (2) The mRNA level of NF-κB in rats of DS group (0.577±0.097) was higher than that in NS group (0.433±0.112, t=-3.147, P<0.05), but less than that in DOVX group (0.696±0.090, t=-2.862, P<0.05). (3) The levels of PI3K protein (4.3±0.6) and Akt2 protein (3.4±0.7) in DS group were lower than the levels of PI3K protein (5.2±0.4) and Akt2 protein (4.7±0.7) in NS rats (t= 2.654, 3.488, respectively, both P<0.05), but lower than those in DOVX group (3.5±0.6, 2.8±0.5, t=3.473, 2.365, both P<0.05). (4) The level of NF-κB protein in DS group (6.5±0.9) was higher than that in NS group (4.9±0.8, t=-3.396, P<0.05), but lower than that in DOVX group (8.1±0.8, t=-2.954, P<0.05).
Conclusion
The expression of PI3K and Akt2 is decreased and the expression of NF-κB is increased in skeletal muscle of ovariectomized diabetic rats, which might lead to insulin resistance.
Key words:
Diabetes mellitus, type 2; Insulin resistance; Ovariectomy; Nuclear transcription factor κ B; Phosphatidylinositol-3-kinase; Serine/Threonine-Protein Kinase 2
Publication Year: 2013
Publication Date: 2013-10-27
Language: en
Type: article
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