ABSTRACT
This study examined the effect of nicotine on the expression of mutant p53 (mt-p53) in bladder cancer rats.The rat models of bladder cancer were established by infusing N-methyl-nitroso-urea (MNU,10 mg/kg every 2 weeks for 8 weeks) into the bladder.Pathological examination on the bladder was conducted to confirm the establishment of the model.All the bladder cancer rats were randomly divided into an MNU group and 3 nicotine groups.In the nicotine groups,the rats were intragastrically administered nicotine at different concentrations (25,15,5 mg/kg respectively)3 times per week for 8 weeks.The mt-p53 expression was detected by the immunohistochemical method.The results showed that rat bladder cancer models developed histopathological changes of bladder transitional cell carcinoma.The positive rate of mt-p53 expression in the 3 nicotine groups (25,15,5 mg/kg) was 75.00％,58.33％ and 41.67％ by the 14th week,respectively,significantly higher than that in the MNU group (33.33％) (all P＜0.05).The mt-p53 expression rate was positively correlated with the medication dose and time (P＜0.05).It is concluded that nicotine may play an important role in the development of bladder cancer partially by increasing the expression of mt-p53.
ABSTRACT
A new artificial somatic-autonomic neuroanastomosis has been established in male rats with spinal cord injury(SCI).Anorectal manometry and neural retrograde tracing were conducted in this animal model to analyze the mechanisms and the effects on recovery of anorectal function.The left L4 ventral root(L4VR)was intradurally micro-anastomosed to the L6 ventral root(L6VR)to establishthe new regenerated neural pathway.Three months later the spinal cord was completely transected at the T9-10 level.Eight weeks later the model rats were randomly divided into two groups.The rats in the group 1(n=8)were applied for anorectal manometry,and those in the group 2(n=4)were used for neural retrograde tracing study with fluorogold(FG)and dextran tetramethylrhodamine(TMR).The results of anorectal manometry showed the new reflex pathway could induce rectum to contract and simultaneously electric activity of external anal sphincter(EAS)to become weak or disappearing (indicating synergetic relaxation of EAS).FG and TMR dual labeled neurons with round and elliptical shape were mainly observed in L4 angulus anterior of model rats.The regenerated neural pathways were effective to improve the rectum external sphincter synergetie status and restore the anorectal function.