Morpholgic changes and transforming growth factor β1 expression in kidneys of diabetic rats and the rats with high sugar diet

Objective To study the role of hyperglycemia in transforming growth factor β1 (TGF-β1) expression and morpholgic changes of the kidneys in diabetic rats and rats with high sugar diet. Methods Thirty-five rats were randomly divided into three groups: diabetic group(D group, n=15), high-sugar diet group (H group, n=10), control group (C group, n=10). Diabetic model rats were established as D group by intra-peritoneal injection of streptozotocin (insulin antagonist). At last 10 rats were successfully established for models. The rats in C group were fed with common diet. The rats in D group and H group were fed with high sugar. After 16 weeks, fasting blood glucose level, urine protein and kidney quality coefficient of all the rats in three groups were measured. Then histological changes of pancreas and kidney were observed by HE staining. Ultrastructural changes of nephridial tissues were viewed by transmission electron microscope; TGF-β1 expression in nephridial tissues was detected by immunohistochemistry and Western blot. Results (1) 24-hour urine protein quantities of the C group, D group and H group were (15.93±8.43) mg, (97.76±7.83) mg, (56.28±10.36) mg, and FBG levels: (8.2401±1.3307) mmol/L, (19.8726±1.8973) mmol/L, (16.2418±2.3464) mmol/L respectively. Those indexes in D group and H group were higher than the C group, and those in D group were higher than H group(all P<0.05). Kidney quality confficient of the D group was higher than that of C group (P<0.05), which was not different with H group. And there was no difference between H group and C group. (2)Compared with C group, pancreatic islet volume in H group reduced. While pancreatic lobule dwindled, pancreatic islet was atrophy and even disappeared in D group. An area ratio of kidney fibrosis and thickness of glomerular basement membrane all significantly increased in H group and D group compared to C group, and degree of increase on those was less in H group than D group. (3)Immunohistochemical result showed that TGF-β1 expression of nephridial tissues was only weakly in rats of C group. TGF-β1 expression of rats in D group and H group were obviously higher than that of C group (P<0.05), and that in D group was higher than H group(P<0.05). Western blot result showed that the band gray level of TGF-β1 expression of nephridial tissues in D group and H group were higher than C group (P<0.05) and there was different between D group and H group (P<0.05). Conclusions There is high TGF-β1 expression in kidneys of diabetic rats and high sugar diet rats, and morphologic changes of diabetic nephropathy can be found. Hyperglycemia may be an important initiation factor for diabetic nephropathy. Key words: Hyperglycemia;  Diabetes mellitus, experimental;  Diabetic nephropathies; Transforming growth factor beta;  Histology