Preparation and evaluation of animal model of diabetic microvascular complications / 中华眼底病杂志

ABSTRACT

Objective:To establish a rat model of diabetic microangiopathopathy and simulate the biochemical and pathological changes of diabetic retinal and renal microangiopathopathy.Methods:Forty healthy male Sprague-Dawley rats were randomly divided into blank group and model group (10 and 30 rats, respectively). After the rats in blank group and model group were fed ordinary diet and high-fat and high-sugar diet for 5 weeks, respectively, the rats in model group were injected with 1% streptozotocin (STZ) through the abdominal cavity at the dose of 35 mg/kg to establish a type 2 diabetes model. After modeling, the rats were continuously fed until the 10th week (4 weeks after modeling), the general conditions of the rats were observed, and samples were collected for follow-up experiments. Serum creatinine (CREA), triglyceride (TG), total cholesterol (TC), high density lipoprotein (HDL-C), low density lipoprotein (LDL-C), microalbuminuria, urinary creatinine (UCr) and urine sugar were detected. Calculate the kidney index and microalbumin/urinary creatinine ratio (UACR). Optical coherence tomography angiography (OCTA) was used to observe the vascular changes and non-perfusion area of retinal superficial capillary plexus. The morphological and structural changes of kidney and retina were observed by hematoxylin-eosin and periodate Scheff staining. The expression of nerve fibers and nucleus of Müller cells in rat retina was observed by immunofluorescence staining. Ultrastructural results of retina were observed by transmission electron microscope. Independent sample t test was used for comparison between groups. Results:Four weeks after modeling, compared with blank group, the body weight of rats in model group was significantly decreased, and random glucose was significantly increased, with statistical significance ( t=5.755, -51.291; P<0.05). Renal index, urinary glucose and UACR were significantly increased, while UCr was significantly decreased, with statistical significance ( t=10.878, 137.273, 3.482,-6.110; P<0.05). CREA decreased, TG, TC, HDL-C, LDL-C increased, and the differences were statistically significant ( t=-28.012, 33.018, 118.018, 13.585, 16.480; P<0.05). OCTA examination showed that there was no perfusion area of shallow retinal capillaries. The optical microscope showed that the inner boundary membrane of retina in model group was swollen and thickened, the surface was uneven, the inner and outer nuclear layer cells were disordered and the density decreased. Glomerular congestion was accompanied by cortical tubular epithelial swelling, widening of the mesangial area, and thickening of the basement membrane. The results of immunostaining showed that the inner and outer plexiform layers of the retina showed lamellar strong green fluorescence expression, and the inner and outer nuclear layers showed scattered dot green fluorescence expression. Transmission electron microscopy showed that the basal membrane of retinal microvessels in model group was slightly thickened, vascular endothelial cells edema, endothelial nucleus and perinucleus contraction, nuclear membrane contraction, mild mitochondrial swelling, vacuolation. Conclusion:High-glucose and high-fat feeding plus a single intraperitoneal injection of STZ 35 mg/kg can successfully establish a microangiopathic model of type 2 diabetes.