ABSTRACT
Objective To explore the relationship between the expression of nerve growth factor (NGF) in bladder tissue of Sprague-Dawley rats with diabetes mellitus and the changes of bladder structure and urodynamics.Methods Sixty-three Sprague-Dawley rats were selected and divided into diabetic group (n =33) and control group (n =30).The diabetes mellitus model was made by injecting of steptozotocin (STZ) into the tail vein of rats in the diabetic group;the rats in control group were injected the same volume of citrate buffer solution.The 24 h urinary volume was detected by using metabolic cage;the function of bladder was detected by using Medlab bio-signal collection system;the expression of NGF in the bladder tissue of rats was detected by Western blot;the bladder structure was observed by using light microscope and transmission electron microscope (TEM).Results Four,eight and twelve weeks after the success of diabetic rat model,the level of blood glucose of rats in diabetic group was significantly higher than those in the control group (P ＜ 0.05);the body weight of rats in diabetic group was significantly lower than that in the control group (P ＜ 0.05).The 24 h urinary volume of rats in diabetic group was significantly increased compared with control group (P ＜ 0.05).The maximum capacity of bladder and residual urine volume of bladder and elasticity of bladder of rats in diabetic group were significantly higher than those in the control group (P ＜ 0.05);the maximum bladder pressure of rats in diabetic group was significantly lower than that in the control group (P ＜ 0.05);and the changes of all above indexes of rats in diabetic group were time-dependent(P ＜ 0.05).The expression of NGF in bladder tissues of rats in diabetic group was significantly lower than that in the control group (P ＜ 0.05),and the change of NGF expression in diabetic group was time-dependent (P ＜ O.05).In diabetic group,the bladder smooth muscle was hypertrophic,the organization of smooth muscle was diverse and lose,and the muscle bundle fracture was observed;in control group,the bladder smooth muscle arranged orderly,and the shape was consistent,the structure of fascicle was compact.The condensation and margination of nuclear chromatin and mitochondria swelling were observed in diabetic group;while the bladder tissues in control group showed homogeneous nuclear and mitochondria without fracture and swelling.Conclusion The decrease of the expression of NGF in bladder tissues of diabetic rats can decrease the systolic function of bladder and change the morphology of detrusor and these changes show a time dependence.