The effect of vasectomy on pituitary-gonadal function in men

Survivin downregulation is associated with vasectomy-induced spermatogenic damage and apoptosis

OBJECTIVE

To evaluate the expression of the apoptotic genes survivin, Bax and Bcl-2 in vasectomized rabbits and to determine their relation with vasectomy-induced spermatogenic impairment and germ cell apoptosis.

MATERIALS AND METHODS

Twelve adult rabbits (6-12 months old) were divided into three groups: sham control, unilateral vasectomy or bilateral vasectomy. Six months after vasectomy, testicular tissue was analyzed for germ cell apoptosis and DNA fragmentation by the TUNEL assay and gel electrophoresis, respectively. Spermatogenesis was assessed using the Johnsen score. The relative gene expression of survivin, Bax and Bcl-2 was measured using reverse transcription followed by real-time PCR.

RESULTS

Compared to sham animals, a significant decrease in testicular survivin mRNA levels was measured in the two vasectomy animal groups (p < 0.05). This was accompanied by a significant increase in the Bax:Bcl-2 ratio in the vasectomized animals (p < 0.05). In addition, these data showed positive correlation with enhanced apoptotic index, damage to spermatogenesis and DNA fragmentation after vasectomy.

CONCLUSION

These findings demonstrate that vasectomy-induced damage to spermatogenesis due to testicular apoptosis may be associated with survivin downregulation and Bax overexpression.

Effects of vasectomy on spermatogenesis and fertility outcome after testicular sperm extraction combined with ICSI

BACKGROUND

Each year 40,000 men have a vasectomy in the UK whilst another 2400 request a reversal to begin a second family. Sperm can now be obtained by testicular biopsy and subsequently used in assisted conception with ICSI. The study aims were to compare sperm yields of men post-vasectomy or with obstructive azoospermia (OA) of unknown aetiology with yields of fertile men and to assess any alteration in the clinical pregnancy rates after ICSI.

METHODS

Testicular tissue was obtained by Trucut needle from men who had undergone a vasectomy >5 years previously or had OA from other causes and from fertile men during vasectomy. Seminiferous tubules were milked to measure sperm yields. Numbers of Sertoli cells and spermatids and thickness of the seminiferous tubule walls were assessed using quantitative computerized analysis.

RESULTS AND CONCLUSIONS

Sperm yields/g testis were significantly decreased in men post-vasectomy and in men with OA, relative to fertile men. Significant reductions were also observed in early (40%) and mature (29%) spermatid numbers and an increase of 31% was seen in the seminiferous tubule wall (basal membrane and collagen thickness) of vasectomized men compared with fertile men. Clinical pregnancy rates in couples who had had a vasectomy were also significantly reduced.

Possible biological mechanisms for a relationship between vasectomy and prostatic cancer

Four hypotheses have been reviewed, each of which might serve as a hypothetical biological explanation for a relationship between vasectomy and prostate cancer. The endocrine hypothesis is the only one of these with any firm data to support it, although the majority of the available data does not lend credibility to that theory. The other hypotheses are purely speculative with no hard data to support them. In conclusion, it seems highly unlikely, but not impossible, that there is a biological mechanism supporting a relationship between vasectomy and prostate cancer.

The long-term influence of vasectomy on prostatic volume and morphology in man

During the past two decades several papers have described the changes in prostatic secretory capacity following vasectomy. Based upon results indicating a reduction of secretory function, it was suggested that even prostatic size and the incidence of benign prostatic hyperplasia (BPH) might be altered after the operation. In this study, which included 56 males who had been vasectomized 8 years previously and 56 age-matched control persons, transrectal ultrasonic scanning of the prostate was used for exact measurements of the prostatic volume and for the investigation of intraprostatic echo pattern. The total prostatic volume, the volume of the periurethral gland, and the volume of the peripheral zone were not influenced by the vasectomy; nor was the growth rate of these zones affected. In the vasectomy group, the frequency of adenomatous prostates was 19.6%, whereas 30.3% of prostates in the control group had ultrasonic signs of BPH. However, this is not a statistically significant difference. Subdividing the material according to age did not reveal altered BPH frequency in any age group when vasectomized and controls were compared.

Relationships between serum FSH level and the size of testis in azoospermic patients

Sixty-eight out of 700 patients proved to be azoospermic at our Andrology Clinic between 1981 and 1983. According to the serum FSH level and testis size, three main diagnostic groups were established: 1. patients with occlusion but testis size and FSH level normal; 2. patients with smaller testis size and increased FSH level and primary spermatogenetic disorder; 3. non-palpable testis and increased serum FSH level referring also to testicular disorder. No correlations were found between serum LH and testosterone levels and testicular volume.

The hormonal and immunological status of vasectomised men

The concentration of FSH, LH, testosterone and sperm agglutinating and cytotoxic antibodies have been determined in 87 men at varying time intervals after vasectomy. The results indicated that vasectomy is not associated with statistically significant changes in any of these parameters. Furthermore, no correlation existed between the development of sperm antibodies and the peripheral endocrine status of an individual.

The endocrine effects of vasectomy: a prospective five-year study

A prospective study of plasma luteinizing hormone (LH) and testosterone in 54 men for 5 years following vasectomy revealed no significant continuing alteration in either testosterone or LH. Plasma LH levels 1 year after operation were higher than preoperative levels but did not increase further. Stimulation studies (4 years postvasectomy) using human chorionic gonadotropin confirmed acceptable Leydig cell functional reserve.

Changing profiles in vasectomy subjects in the past decade

Two groups of vasectomy patients were reviewed: 376 men operated upon between 1968 and 1971 and 608 between 1974 and 1978. Average age, length of marriage, and number of living children prior to vasectomy were greater in the first group (P less than 0.01). The results are compatible with the idea that couples are planning smaller families and turning increasingly to vasectomy as a reliable permanent birth control method immediately following the completion of their families.