Experimental research of alteration of M_3 receptor in ureteral smooth muscle cells on rat of partial unilateral ureteral obstruction

Objective To investigate the changing regulation of M 3 receptor in mRNA and protein in smooth muscle cells in rats after partial unilateral ureteral obstruction(PUUO).Methods 80 male Wistar rats were divided into 4 groups randomly:the 8-week PUUO group(n=20),8-week control group(n=20),16-week PUUO group(n=20) and 16-week control group(n=20).The upper half section of left ureters(n=40) in the two PUUO groups were embedded into the psoas muscles,while the rats in the two control groups(n=40) were only received laparotomy.The ureters were cut at different experimental time(the 8th week and the 16th week separately) after the models were established.Then,the mRNA and the protein expression of M 3 receptor were detected by the RT-PCR and Western-blotting.Results According to the results of RTPCR,the mRNA expression level of M 3 receptor in 8-week PUUO group was higher than that of 8-week control group(55.16±3.94) vs(36.48±3.87),the 16-week PUUO group was lower than 16-week control group(19.37 ±3.70) vs(37.39± 3.65),8-week PUUO group was higher than that of the 16-week PUUO group,the differences were all statistically significant(all P0.05).According to the results of Western blotting experiments,the M 3 receptor protein expression level in the 8-week PUUO group was higher than that of 8-week control group(27.13±1.77) vs(21.36±2.69),the 16-week PUUO group was lower than 16-week control group(19.41±1.37) vs(23.43±1.58),the differences were all statistically significant(all P0.05),the difference between the 8-week control group and 16-week control group was no statistical significance(P0.05).Conclusion The series of experiments demonstrate an increase of M 3 receptor in smooth muscle cells in PUUO rats at 8 weeks while a decrease of that at 16 weeks,which provides a foreshadowing of the clinical researchfor the next step.