Experimental Study Of The Apoptosis Of Germ Cell In Adolescent Rats With Varicocele

Background and Objective: Varicocele is a common cause of male infertility, nowadays the study to the effects of varicocele on the apoptosis of germ cell is in the beginning stage,the correlated report was little,and the results of all the study were different.Recently many people study on adolescent varicocele,some study told us that pathologic change of testis in adolescent varicocele was as same as adults,and the impair to testis can develop,and was related to the infertility.The study on adolescent varicocele patients was limited,so we created experimental model of varicocele in adolescent rats,and we study on the apoptosis of spermatogenic cell and testis histology in the different time rats by TUNEL (in situ terminal deoxynucleotityl transferase-mediated dUTP nick end-labeling) and electron microscopy,to explore the mechanism of infertility by varicocele.and provide experimental evidence to the choice of operative time in varicocele.Materials and methods: The study comprised 60 male SD rats(6 weeks) divided into 2 groups randomly:test and control.In the test group,we created the model by partial ligation of the left renal vein.According to different time of model,test group was divided into 3 groups(every group had 10 rats). A1 group:the rats were killed 2 weeks after the model created, A2 group:the rats were killed 4weeks after the model created, A3 group:the rats were killed 8 weeks after the model created. In the control group, the left renal vein was exposed without interference with it. According to different time of model,test group was divided into 3 groups(every group had 10 rats). B1 grouprthe rats were killed 2 weeks after the model created, B2 grouprthe rats were killed 4weeks after the model created, B3 group:the rats were killed 8 weeks after the model created.When the model time is up,we did as follows: 1.measure testicular vein diameter. 2. weight the testis. 3. detect apoptosis of spermatogenic cell by TUNEL. 4. observe testis ultrastructure by electron microscopy.Results: 1. internal spermatic vein diameter In test group, left testicular vein were more dilatate than the right,and there was significant difference between the left and the right(p<0.001).In control group,no testicular vein were dilatate, there was no difference between the left and the right(p>0.05). There was significant difference between the left testicular vein in the A1 group and Bl group, the A2 group and B21 group, the A3 group and B3 group (p<0.001). 2. Testis weight There was no significant difference of testis weight between the 2 weeks test group and the 2 weeks control group, the 4weeks test group and the 4 weeks control group(p>0.05). there was significant difference between left testis weight and right testis weight in 8 weeks test group(p<0.05), and there was significant difference of left testis weight between the 2 weeks test group and the 4weeks test group(p<0.05) .and there was significant difference of left testis weight between 8 weeks test group and 8 weeks control group(p<0.001). 3. apoptosis of germ cell There was significant difference of incidence of apoptosis of germ cell between the left and the right testis in 2 weeks,4 weeks and 8 weeks group(p<0.001),and between the left testis in the test group and control group of 2 weeks,4 weeks and 8 weeks(p<0.001), and between the right testis in the test group and control group of 2 weeks,4 weeks and 8 weeks(p<0.001). there was no significant difference of incidence of apoptosis of germ cell between the left and the right testis in each control group(p>0.05),but was significant difference between 2 weeks test group and 4 weeks test group and 8 weeks test group (pO.OOl). 4. histology alteration In the testicular spermatogenic cells,chromosome condensation and decomposition were seen.The decomposition of the membranous composition of the apoptotic spermatogenic cells occurred,nuclear membrane became smooth,the round apoptotic bodies transmittedtoward cellular membrane. The apoptotic testicular Leydig cells also occurred.conclusions Experimental varicocele can cause the increase of incidence of apoptosis of germ cell in bilateral testis, incidence of apoptosis was increased remarkably in experimental group than in control group (pO.OOl), especially in the left testis,and there was significant difference between the left and the right testis. Unilateral varicocele can impair bilateral testis.moreover,with the time of the experimental varicocele model prolonged,the impairment to testis will be greater. The increase of apoptosis of germ cell reduce the count of functional cell,and influence the male infer,it maybe one of the mechanism of varicocele causing male sterility.