Objective To explore the effects of pelvic nerves denervation (PND) on the expression of transit potential receptor vanilloid 1 (TRPV1) in distal colonic mucosa of rats.Methods The experimental study was conducted.One hundred and eight adult male rats were randomly divided into the control group,sham operation group and PND group:(1) 36 rats in the control group remained untreated and were fed regularly;(2) 36 in the sham operation group received open exclusion for 15 minutes,and then sew up the incision;(3) 36 in the PND group received laparotomy with pelvic nerve transection before abdominal closure.The expression of TRPV1 protein in distal colonic mucosa was respectively detected by Western blot at postoperative day 1,3 and 7.Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) was used to detect the mRNA level of TRPV1 in the distal colonic mucosa.Measurement data with normal distribution were represented as (x)±s.Repeated measurement data were analyzed by repeated measures ANOVA.Comparisons at the same time intervals among the 3 groups were analyzed using one-way ANOVA.Pairwise comparison was done by the independent samples t test.Results (1) The results of immunohistochemical staining:the average density of TRPV1 in distal colonic mucosa at postoperative day 1,3 and 7 was respectively 0.180±0.016,0.179±0.015 and 0.183±0.026 in the control group,with no statistically significant difference (F=0.088,P＞0.05).The average density of TRPV1 in distal colonic mucosa at postoperative day 1,3 and 7 was respectively 0.132±0.017,0.160±0.023 and 0.173±0.020 in the sham operation group,with a statistically significant difference (F=8.699,P＜0.05).The average density of TRPV1 in distal colonic mucosa at postoperative day 1,3 and 7 was respectively 0.057± 0.009,0.122±0.016 and 0.180± 0.016 in the PND group,with a statistically significant difference (F =113.315,P ＜ 0.05).There were statistically significant differences in the average density of TRPV1 at postoperative day 1 and 3 among the 3 groups (F =108.960,15.218,P＜ 0.05),while significant differences were respectively detected between the control group and the sham operation group or the PND group at postoperative day 1 (t =5.025,15.979,P＜0.05),and a significant difference was also detected between the sham operation group and the PND group (t =9.590,P＜0.05).There was no statistically significant difference in the average density of TRPV1 between the control group and the sham operation group at postoperative day 3 (t =1.670,P＞0.05),while significant differences were respectively detected between the control group and the PND group and between the sham operation group and the PND group (t=6.543,3.361,P＜0.05).There was no statistically significant difference in the average density of TRPV1 at postoperative day 7 among the 3 groups (F=0.518,P＞0.05).(2) The results of Western blot:the relative expressions of TRPV1 in distal colonic mucosa at postoperative day 1,3 and 7 were respectively 1.02±0.13,1.00±0.15 and 1.00±0.10 in the control group,with no statistically significant difference (F=0.084,P＞0.05).The relative expressions of TRPV1 in distal colonic mucosa at postoperative day 1,3 and 7 were respectively 0.51±0.13,0.93±0.14 and 1.01±0.16 in the sham operation group,with a statistically significant difference (F =20.930,P＜0.05).The relative expressions of TRPV1 in distal colonic mucosa at postoperative day 1,3 and 7 were respectively 0.30±0.10,0.70±0.10 and 1.07±0.16 in the PND group,with a statistically significant difference (F=61.441,P＜0.05).There were statistically significant differences in the relative expressions of TRPV1 at postoperative day 1 and 3 among the 3 group (F=58.014,8.841,P＜0.05),while significant differences were respectively detected between the control group and the sham operation group or the PND group at postoperative day 1 (t =6.677,11.145,P＜0.05),and significant difference was also detected between the sham operation group and the PND group (t =3.287,P＜ 0.05).There was no statistically significant difference in the relative expressions of TRPV1 between the control group and the sham operation group at postoperative day 3 (t =0.798,P＞0.05),while significant differences were respectively detected between the control group and the PND group and between the sham operation group and the PND group (t=4.127,3.398,P＜0.05).There was no statistically significant difference in the relative expressions of TRPV1 at postoperative day 7 among the 3 group (F=0.428,P＞0.05).(3) The results of RTqPCR:the mRNA levels of TRPV1 in distal colonic mucosa at postoperative day 1,3 and 7 were respectively 1.00±0.15,1.10±0.21 and 1.09±0.18 in the control group,with no statistically significant difference (F=0.489,P＞0.05).The mRNA levels of TRPV1 in distal colonic mueosa at postoperative day 1,3 and 7 were respectively 0.58±0.12,0.99±0.19 and 1.13±0.23 in the shan operation group,with a statistically significant difference (F=13.964,P＜0.05).The mRNA levels of TRPV1 in distal colonic mucosa at postoperative day 1,3 and 7 were respectively 0.31±0.10,0.67±0.12 and 1.09±0.19 in the PND group,with a statistically significant difference (F=44.642,P＜0.05).There were statistically significant differences in the mRNA levels of TRPV1 at postoperative day 1 and 3 among the 3 group (F=44.653,9.700,P＜0.05),while significant differences were respectively detected between the control group and the sham operation group or the PND group at postoperative day 1 (t=5.233,9.264,P＜0.05),and significant difference was also detected between the sham operation group and the PND group (t=4.127,P＜0.05).There was no significant difference in the mRNA levels of TRPV1 between the control group and the sham operation group at postoperative day 3 (t =0.995,P＞0.05),while significant differences were respectively detected between the control group and the PND group and between the sham operation group and the PND group (t =4.411,3.505,P＜0.05).There was no statistically significant difference in the mRNA levels of TRPV1 at postoperative day 7 among the 3 group (F=0.099,P＞0.05).Conclusion The expression of TRPV 1 in distal colonic mucosa of rats is significantly down-regulated after pelvic nerves denervation,however,it is gradually recovered with passage of time,which is consistent with the trend of gradual recovery of colonic transit function after pelvic nerve injury.

OBJECTIVETo establishment and verify pelvic nerve denervation (PND) model in mice.

METHODS(1) Establishment of models. Seventy-two healthy male SPE class C57 mice with age of 7 weeks and body weight of (25±1) g were chosen. These 72 mice were randomly divided into PND group containing 36 mice and sham operation group containing 36 mice. Referring to the establishment method of PND rats, after anesthesia, a laparotomy was performed on the mouse with an abdominal median incision. Under the dissection microscope, the pelvic nerves behind and after each sides of the prostate gland were bluntly separated with cotton swabs and cut with a dissecting scissor. After the operation, the urination of mice was assisted twice every day. For the mice of sham operation group, the pelvic nerves were only exposed without cutting. (2) Detection of models. Colonic transit test was performed in 18 mice chosen randomly from each group to detect the colonic transit ratio (colored colon by methylene blue/ whole colon) and visceral sensitivity tests was performed in the rest mice to observe and record the changes of electromyogram.

RESULTSThree mice died of colonic transit test in each group. Uroschesis occurred in all the mice of PND group and needed bladder massage to assist the urination. Colonic transit test showed that the colonic transit ratios of sham operation group at postoperative day (POD) 1, 3 and 7 were (0.4950±0.3858)%, (0.6386±0.1293)% and (0.6470±0.1088)% without significant difference (F=0.3647, P=0.058), while in PND group, the colonic transit ratio at POD 7 [(0.6044±0.1768) %] was obviously higher than that both at POD 3[(0.3876±0.1364)%, P=0.022] and POD 1[(0.2542±0.0371)%, P=0.001], indicating a recovery trend of colonic transit function (F=9.143, P=0.004). Compared with the sham operation group, the colonic transit function in PND group decreased significantly at POD 1 and POD 3(both P<0.05), and at POD 7, there was no significant difference between two groups. Visceral sensitivity test showed that the visceral sensitivity of sham operation group at POD 1, 3 and 7 was 24.2808±9.5566, 33.6725±7.9548 and 43.9086±12.1875 with significant difference (F=5.722, P=0.014). The visceral sensitivity of PND group at POD 1, 3 and 7 was 11.7609±2.1049, 21.8415±8.1527 and 26.2310±4.2235 with significant difference as well (F=11.154, P=0.001). The visceral sensitivity at POD 3 and POD 7 was obviously higher than that at POD 1 (P=0.006, P<0.001), and there was no significant difference between POD 3 and POD 7 (P=0.183). Compared with sham operation group, the visceral sensitivity of PND group decreased significantly at POD 1, 3 and 7(all P<0.05).

CONCLUSIONSDenervation of pelvic nerves can obviously decrease the colonic transit function and the visceral sensitivity of mice, but these changes can recover over time, which suggests that the establishment of PND model in mice is successful.

Abdominal Pain ; physiopathology ; Animals ; Autonomic Pathways ; growth & development ; physiopathology ; surgery ; Colon ; innervation ; physiopathology ; Denervation ; methods ; Disease Models, Animal ; Gastrointestinal Transit ; physiology ; Male ; Mice ; Mice, Inbred C57BL ; Nerve Tissue ; growth & development ; physiopathology ; surgery ; Pain, Postoperative ; physiopathology ; Pelvis ; innervation ; physiopathology ; surgery ; Prostate ; innervation ; Recovery of Function ; physiology