ObjectiveTo investigate role and mechanism of protein tyrosine phosphatase 1B (PTP1B) in jejunoileal bypass to treating rats with type 2 diabetes mellitus (T2DM). MethodsTwenty-four T2DM SD rats and 24 normal SD rats were selected randomly by using random number table, then the SD rats with T2DM were randomly divided into jejunoileal bypass operation (DJBO, n=12) group and sham operation (DSO, n=12) group, the SD rats with normal food diet were randomly divided into jejunoileal bypass operation (NJBO, n=12) group and sham operation (NSO, n=12) group. Subsequently, fasting body weight (FBW), fasting plasma glucose (FPG), fasting insulin (FINS), and homeostasis model-insulin resistant (HOMA-IR) index of rats in each group were tested at different time points (before operation, on week 4 and 8 after operation). In addition, expression of PTP1B protein in skeletal muscle was determined by immunohistochemical staining and Western blot method respectively. Results① The FBW before making T2DM model had no significant difference between the rats with high-fat diet and with normal diet (P > 0.05), which on week 4 or 8 after making T2DM model in the rats with high-fat diet was significantly heavier than that in the rats with normal diet (P < 0.05). ② Before jejunoileal bypass operation, the FBW, FPG, FINS, and HOMA-IR index in the DJBO group and the DSO group were significantly higher than those in the NJBO group and the NSO group (P < 0.05), respectively, which had no significant differences between the DJBO group and the DSO group (P > 0.05) and between the NJBO group and the NSO group (P > 0.05). ③ Compared with the values before jejunoileal bypass operation, the FBW, FPG, FINS, and HOMA-IR index on week 4 or 8 after jejunoileal bypass operation were significantly decreased in the DJBO group (P < 0.05); the FBW was significantly increased on week 4 or 8 after jejunoileal bypass operation in the DSO group and the NSO group (P < 0.05), and on week 8 after jejunoileal bypass operation in the NJBO group (P < 0.05). The other indexes had no significant differences between before and after jejunoileal bypass operation in the DSO group, the NSO group, or the NJBO group (P > 0.05). ④ On week 8 after jejunoileal bypass operation, the expression of PTP1B protein in the DSO group was significantly higher than that in the DJBO group, the NSO group or the NJBO group (P < 0.05), which in the DJBO group was significantly higher than that in the NSO group (P < 0.05) or the NJBO group (P < 0.05), which had no significant difference between the NJBO group and the NSO group (P > 0.05). ConclusionJejunoileal bypass could effectively improve insulin resistance and decrease FPG level and FBW of T2DM rats through inhibiting expression of PTP1B protein in skeletal muscle of rat with T2DM.
ObjectiveTo investigate the impact and mechanism of over-expression microRNA-92a (miR-92a) in clinicopathologic feature and prognosis of patients with colorectal cancer (CRC). MethodsThe expression levels of miR-92a and phosphatase and tensin homologue (PTEN) gene in 108 cases of colorectal cancer tissues were detected by using real-time fluorescent quantitative PCR (RT-PCR), and they were categorized as low or high in relation to the median value. Then the association between different levels of miR-92a gene expression and clinicopathologic feature and prognosis of CRC patients were evaluated. Moreover, the relationship between the expressions of miR-92a and PTEN gene were analyzed. ResultsHigh expression of miR-92a not only associated with lymph node metastasis (χ2=8.045, P=0.007), distant metastasis (χ2=5.708, P=0.030), and TNM staging (χ2=6.366, P=0.019) of CRC patients, but also related to the down-regulated of PTEN gene expression (χ2=21.333, P < 0.001). However, up-regulated miR-92a expression was negatively correlated with age, gender, tumor size, tumor location, depth of invasion and tumor differentiation. In addition, Kaplan-Meier survival curves showed that over-expression of miR-92a and low-expression of PTEN gene could potentially predict poor overall survival of CRC patients. ConclusionThe high expression of miR-92a can lead to a poor clinical prognosis of CRC patients through decreasing the expression level of PTEN gene.