A new experimental inbred Wistar rat varicocele model: anatomy of the left spermatic vein and the effect on histology

The effect of the degree of left renal vein constriction on the development of adolescent varicocele in Sprague-Dawley rats

Experimental models have allowed inquiry into the pathophysiology of varicocele (VC) beyond that possible with human patients. A randomized controlled study in rats was designed to clarify the influence of the degree of left renal vein constriction on the development of adolescent VC. Fifty adolescent male Sprague–Dawley rats (Rattus norvegicus) were randomly assigned to five groups of 10: the experimental groups (I–IV) underwent partial ligation of left renal veins with 0.5-, 0.6-, 0.7-, and 0.8-mm diameter needles, respectively. The control group (V) underwent a sham operation. The diameter of the left spermatic vein (LSV) was measured at baseline and 30 days postoperatively. In addition, the lesion of the left kidney was examined with the naked eye and assessed by Masson's trichrome staining. VC was successfully induced in 2 (20%), 4 (40%), 7 (70%), and 10 (100%) rats in groups I–IV, respectively. The other rats failed to develop VCs primarily due to left renal atrophy. No VC was observed in group V. The postsurgical LSV diameters in VC rats in groups III and IV were 1.54 ± 0.16 and 1.49 ± 0.13 mm, respectively (P > 0.05), and their increments were 1.36 ± 0.10 and 1.31 ± 0.10 mm, respectively (P > 0.05). These results suggest that suitable constriction of the left renal vein is critical for adolescent VC development. In addition, the 0.8-mm diameter needle may be more suitable for inducing left renal vein constriction in adolescent rat models.

Resveratrol improves reproductive parameters of adult rats varicocelized in peripuberty

The aim of this study was to investigate the protective action of resveratrol against the reproductive damage caused by left-sided experimental varicocele. There was a reduction of testicular major axis in the varicocele group when compared with the other groups; the testicular volume was reduced in varicocele group in comparison to the sham–control and resveratrol groups. The frequency of morphologically abnormal sperm was higher in varicocele and varicocele treated with resveratrol groups than in sham–control and resveratrol groups. The frequency of sperm with 100% of mitochondrial activity and normal acrosome integrity were lower in varicocele group than in varicocele treated with resveratrol, sham–control and resveratrol groups. Sperm motility was also reduced in varicocele group than in other groups. The sperm DNA fragmentation was higher in varicocele group than in other groups. Testicular levels of malondialdehyde were higher in varicocele and varicocele treated with resveratrol groups. The varicocele and varicocele treated with resveratrol groups had a significantly higher frequency of TUNEL-positive cells than sham–control and resveratrol groups; however, immunolabeling of the testes from varicocele treated with resveratrol group showed a lower number of apoptotic germ cells in comparison with the left testis of rats of the varicocele group. Reproductive alterations produced by varicocele from peripuberty were reduced by resveratrol in adulthood. Resveratrol should be better investigated as an adjuvant in the treatment of varicocele. Daily administration of resveratrol to rats with varicocele from peripuberty improves sperm quality in the adulthood.

Varicocele-caused progressive damage in bilateral testis and sertoli cell-only syndrome in homolateral testis in rats

Background

We aimed to investigate whether varicocele (VC) in rats can cause Sertoli cell-only syndrome (SCOS).

Material/Methods

Forty adolescent SD rats were randomly divided into 4 groups: 4-weeks control group, 4-weeks experimental group, 12-weeks control group, and 12-weeks experimental group. Left varicocele models were introduced by partially ligating left kidney veins for the experimental groups, and the sham surgery groups as controls were executed with exactly the same surgery as in the experimental groups except for the ligation. Rats in control and experimental groups for 4 and 12 weeks were killed after laparotomy at 4 and 12 weeks, respectively, the testes were taken out and fixed in fixative containing 4% polyformaldehyde, then were stained by hematoxylin and eosin (HE). The density and viability of sperm were analyzed by computer-aided sperm analysis.

Results

Compared with rats in 4-weeks and 12-weeks control group, histological structures of bilateral testes in both experimental groups were impaired, most of them showing as focal focuses. The pathological changes of testes in rats of the 12-weeks experimental group were bilateral, and included atrophy of seminiferous tubules, turbulence of spermatogenic cells in seminiferous tubules, defluvium of most spermatogenic cells, abortion of spermatogenesis, and degradation of spermatogenic epithelia. One rat in the 12-weeks experimental group was shown having SCOS, with the spermatogenic cells in seminiferous tubules completely flaked, degraded, or absent, and only Sertoli cells lined the seminiferous tubules.

Conclusions

Laboratory VC caused progressive impairment of homolateral testes, and SCOS could be induced when the damage was severe. Our results indicate that asthenozoospermia, azoospermia, and SCOS can be prevented by the earlier treatment of VC.

The comparison of two experimental rat varicocele models and their effect on sperm quality

OBJECTIVE

To develop a modified rat varicocele model.

METHODS

300 male Sprague-Dawley rats were selected. In 82 rats (classic group, CG), this was achieved by dissecting the left renal vein and ligating it using a 0.8-mm metal clip and 3-0 silk suture proximal to the inferior vena cava, followed by removal of the bar. In 118 rats (modified group, MG), in addition to the partial ligation of the left renal vein, the communicating branch was fully ligated. In 100 rats (sham operation group, SG), the left renal vein and communicating branches were dissected, but not ligated. The seminal fluid was aspirated and the diameters of the left spermatic veins were analyzed. Three months later, the examination was performed again.

RESULTS

The diameters were 0.16 ± 0.1 mm and 1.88 ± 0.1 mm before and after operation, respectively, in the CG (p < 0.01), and 0.15 ± 0.05 mm and 2.0 ± 0.1 mm in the MG (p < 0.01). Postsurgical diameters in the CG and MG were 1.88 ± 0.1 mm and 2.0 ± 0.1 mm (p > 0.5), and 0.16 ± 0.1 mm and 0.16 ± 0.11 mm in the SG (p > 0.5). Semen parameters in the CG had significant differences before and after the operation (p < 0.01), were significantly lower in the MG (p < 0.01), and had no significant differences in the SG (p > 0.5).

CONCLUSION

Simple partial ligation of the renal vein combined with ligation of the communicating branch leads to acceptable models for varicocele.