Differential expression and localization of neuropeptide Y peptide in pancreatic islet of diabetic and high fat fed rats.

Neuropeptide Y (NPY) inhibits insulin secretion. Increased numbers of pancreatic islet cells expressing NPY have been observed in type 1 diabetic rats. To understand the functional significance of NPY expression in islet cells, we investigated the effects of high fat feeding and diabetic conditions on the expression and location of NPY expressing cells in normal and diabetic rats. Twenty rats were maintained on either normal chow (ND) or a high fat dietary regimen (HFD) for 4 weeks. In half of each group, type 1 or type 2 diabetes (groups T1DM and T2DM, respectively) was induced by injection of streptozotocin. At 8 weeks rats were euthanized and the pancreases were processed for immunofluorescence labeling (NPY/insulin, NPY/glucagon, NPY/somatostatin, and NPY/pancreatic polypeptide). Compared with the ND group, HFD rats had significantly fewer alpha cells, but beta cells were similar, while T1DM and T2DM rats showed significant increases in the proportions of alpha, delta, and PP cells. Robust increases in NPY-positive islet cells were found in the HFD, T1DM, and T2DM rats compared with ND controls. In ND rats, 99.7% of the NPY-positive cells were PP cells. However, high fat feeding and diabetes resulted in significant increases in NPY-positive delta cells, with concomitant decreases in NPY-positive PP cells. In summary, high-fat feeding and diabetes resulted in changes in the hormonal composition of pancreatic islet and increased number of NPY-expressing islet cells. Under diabetic conditions NPY expression switched from predominantly a characteristic of PP cells to predominantly that of delta cells. This may be a factor in reduced pancreatic hormone secretion during diabetes.

Comparison of glucose and lipid metabolism in two types of Parkinson’ s disease rat models / 解剖学报

Objective To select an ideal Parkinson ’ s disease ( PD) animal model with metabolic abnormalities for subsequent experimental studies .Methods A total of 62 Sprague-Dawley male rats were randomly divided into four groups:damaged medial forebrain bundle ( MFB) model group, damaged medial forebrain bundle ( MFB) sham group, damaged Striatum model group and damaged Striatum sham group .After detecting the rotation experiment , successful model rats of two groups were selected to detect the changes of food intake , body weight , blood glucose and intra-abdominal adipose tissue.Results It was easier to produce a PD model by destroying MFB than striatum .Compared with sham-operated rats, MFB model rats showed significant abnormality both in reduction of body weight [(218.1 ±13.99) g vs (252.7 ±10.1)g, P<0.05] and high blood glucose appeared at 15min and 30min after introperitoneal glucose tolerance test ( IPGTT) .Their perirenal white adipose tissue was significantly reduced ( both left and right side ) .Striatum model rats only appeared decreased food intake [(13.95 ±0.25)g vs (20.23 ±0.86)g, P<0.001] and impaired glucose regulation at 15min, 30min and 60min after IPGTT.Their body weight and adipose tissue did not change significantly .Conclusion No matter in the success rate or metabolism-related indicators , MFB damaged rat model of PD is more suitable to study PD patients with abnormal lipid metabolism compared with Striatum rat model .