Effects of complete denervation of sympathetic adrenergenic nerve on biological behaviors of prostate cancer in mice

Abstract

Objective To investigate the effects of complete denervation of sympathetic adrenergic nerves on the biological behaviors of prostate cancer in C57BL/6 mice. Methods Fifty male C57BL/6 mice, 10 weeks old, were randomly divided into two groups. By using a micro-syringe, RM-1 cells (0. 5 ×106) were injected into bilateral dorsal prostate capsules of mice, at the same time, bilateral hypogastric sympathetic nerves of the mice were cut (experimental group) or not (control group). At the sixth day postoperation, 5 mice were sacrificed in each group every three days to observe the local growth, invasion and metastasis of prostate cancer to pelvic nodes and other organs. An immunohistochemical determination of the hypogastric nerves was made by using an antibody against tyrosine hydroxylase ( TH) , a marker for sympathetic nerves. At the 15th day, 10 mice left were fed to death to calculate the life span of tumor-bearing mice. Results The volume of the prostate was gradually increased and confirmed as prostate cancer histologically. The prostate volume in experimental group was (0. 034 ± 0. 008) , (0. 339 ±0. 040) , (0. 829 ±0. 090) , ( 1. 169 ±0. 093) cm3 on the day 6, 9, 12, 15 after operation, respectively,while that in control group was (0.034 ± 0. 008), (0. 316 ± 0. 050), (0. 824 ± 0.071), (1. 236 ±0. 103) cm3, respectively (all P ＞ 0. 05). At the 12th day, muscle tissues around the prostate invasion by prostate cancer were observed in 3 cases of experimental group and 4 cases of control group; at the 15th day, invasion of seminal vesicles and bladder was found in 4 cases of experimental group and 4 cases of control group. Three and 4 mice had metastasis of pelvic nodes at 12th day and 15th day respectively in the experimental group, and 4 and 4 respectively in control group. At the 15th day post operation, in control group, liver parenchyma metastasis and renal pelvis metastasis were observed in 1 and 1 case, respectively, while in experimental group, no distant metastasis was observed. The life span of tumor-bearing mice in the experimental and control groups was (15.80±0.84) and (16.00±0.71) days, respectively (P＞0. 05 ) . Conclusion Complete denervation of sympathetic adrenergic nerves seems to have no significant effects on the local growth, invasion and pelvic nodes metastasis of prostate cancer in C57BL/6 mice, but may have some inhibition effects on its distant metastasis. Key words: Prostatic carcinoma; Sympathetic denervation; Biology; Mouse