Expression of GDNF and AR in Testicular Peritubular Cells of Surgery-induced Cryptorchidism Mice / 中山大学学报(医学科学版)

ABSTRACT

ObjectiveTo investigate the expression of glial cell line-derived neurotrophic factor （GDNF） and androgen receptor （AR） in testicular peritubular cells （TPCs） of cryptorchidism mouse models and explore the theoretical significance of cryptorchidism-induced spermatogenesis dysfunction. MethodsA total of 30 five-week-old male ICR rats were divided randomly by using random number table method into 6 groups. Cryptorchidism was surgically induced in 3 randomly selected groups and the other 3 groups underwent sham surgery as the control groups. On days 4， 7 and 14 after surgery， we harvested the mice testes of the 3 groups and their corresponding control groups， then measured the testicular volumes， analyzed the testicular histopathology and detected the mRNA and protein expression levels of AR and GDNF in TPCs by immunofluorescence， real-time PCR and Western blot. ResultsIn normal control groups， on days 4， 7 and 14 after surgery， the testicular volumes were （125.58±19.22） mm3，（123.45±20.12） mm3， （140.09±13.62） mm3 ， respectively. Clear layers of spermatogenic cells were well arranged and abundant sperm cells were found. Peritubular cells were morphologically homogeneous， with slim-spindle appearance and normal cell thickness. The mRNA expression levels of AR were 1.00±0.05， 1.06±0.07 and 1.19±0.13； GDNF mRNA 1.00±0.04， 1.09±0.05， and 1.10±0.07. The protein expression levels of AR were 1.01±0.01， 0.79±0.02 and 1.01±0.04； GDNF protein （18.68±0.43） pg/mL， （14.39±0.36） pg/mL and （16.88±0.37） pg/mL. In cryptorchidism groups， on days 4， 7 and 14 after surgery， the testicular volumes were （115.64±3.91） mm3， （69.51±14.97） mm3 and （44.86±5.56） mm3， respectively. Spermatogenic cells were disorganized， seminiferous tubules were disrupted， peritubular cells shrank， bent and fractured. The mRNA expression levels of AR were 0.76±0.06， 0.53±0.04， and 0.29±0.02； GDNF mRNA 0.72±0.05， 0.42±0.02 and 0.30±0.03. The protein expression levels of AR were 0.54±0.02， 0.98±0.04 and 0.31±0.01； GDNF protein （8.50±0.34） pg/mL， （17.44±0.32） pg/mL and （6.83±0.34） pg/mL. Statistically significant differences （P < 0.05） were found in 7-day and 14-day testicular volumes between control and cryptorchidism groups but not in the 4-day testicular volume （P > 0.05）. Testicular volumes， AR and GDNF mRNA and protein expression in control groups had no statistically significant difference （P > 0.05）， while those in cryptorchidism groups showed a trend of gradual decline in the amount and the differences between groups were statistically significant （P < 0.05）. ConclusionsIn surgery-induced cryptorchidism mice， after the induction， the expression of AR and GDNF in TPCs showed a gradual decrease over time. AR and GDNF play a major role in mediating the TPCs damage in cryptorchidism. This study provides a theoretical basis for mechanism researches of cryptorchidism-induced spermatogenesis dysfunction.