Blood-testis Barrier In Rats Research Articles

Lycium barbarum Polysaccharide Ameliorates Heat-Stress-Induced Impairment of Primary Sertoli Cells and the Blood-Testis Barrier in Rat via Androgen Receptor and Akt Phosphorylation.

Male infertility induced by heat stress has been attracting more and more attention. Heat stress not only causes apoptosis of spermatocytes but also has adverse effects on Sertoli cells, further damaging spermatogenesis. Lycium barbarum polysaccharide (LBP) is the main bioactive component of Lycium barbarum, which has a protective effect on male reproduction, but its mechanism is still unclear. In this study, our results proved that LBP blocked the inhibitory effect on the proliferation activity of Sertoli cells after heat stress, reversed the dedifferentiation of Sertoli cells induced by heat stress, and ameliorated the structural integrity of the blood-testis barrier. In addition, it increased the expression of the androgen receptor and activated Akt signaling pathway to resist heat-stress-induced injury of Sertoli cells.

Semen Cuscutae-Fructus Lycii improves spermatogenic dysfunction by repairing the blood-testis barrier in rats according to in silico and in vitro methods

Ethnopharmacological relevanceSemen Cuscutae and Fructus Lycii (SC-FL) is a commonly used herbal pair for male infertility treatment. Studies have found that the mechanism of SC-FL treatment may be related to repairing the blood-testis barrier (BTB). The application of network pharmacology can be used to explore the correlation between medicines and diseases and predict the potential pharmacological mechanisms of SC-FL. Aim of the studyThis study aimed to explore the specific effects and mechanisms of SC-FL in repairing the BTB and initially revealed the mechanism of Chinese medicine treating male infertility through network pharmacology and animal experiments. Materials and methodsWe searched databases using the network pharmacology method and performed mass spectrometry analysis. We analyzed and predicted the active ingredients, targets and key pathways of SC-FL in male infertility treatment. Then, we designed animal experiments to verify the results. Thirty-six Sprague-Dawley rats were randomly divided into the normal control group (NC group), spermatogenic dysfunction group (SD group) and SC-FL treatment group (SCFL group). Glucosides of Tripterygium wilfordii Hook. F (GTW) (40 mg/kg/d) was administered for 4 weeks to generate a spermatogenic dysfunction model. The rats in the SCFL group were given the SC-FL suspension (6 g/kg/d) daily. After 4 weeks of treatment, we detected the sperm quality of each group of rats and observed the cell morphology. Western blotting and qRT-PCR were used to detect the expression of BTB-related proteins in testicular tissues. Results213 chemical ingredients of SC and FL were retrieved from the TCMSP database, and 54 effective chemical ingredients were obtained. Mass spectrometry analysis showed the above results were credible. Then, we identified 44 potential targets for the treatment of male infertility, and we plotted a network diagram of the interaction network between the core targets and a diagram of herbal medicine-active ingredient-target-disease interactions. The target genes were enriched according to biological functions, and 22 biological processes, 49 cellular components, 1487 molecular functions, and 122 signaling pathways were obtained. The results of the animal experiments showed that the sperm concentration and motility of the SCFL group were significantly improved compared with those of the SD group. Compared with those in the SD group, the structure and morphology of the Sertoli cells and seminiferous tubules of rats in the SCFL group improved, and the number of spermatogenic cells increased significantly. Western blotting and qRT-PCR results showed that compared with that in the SD group, the expression of p38 MAPK decreased significantly, and the expression of c-Jun, Occludin, ZO-1 and connexin 43 increased significantly in the SCFL group. ConclusionWe predicted that the active ingredients of SC-FL can treat male infertility by interacting with the core targets JUN, IL6, MAPK1, TP53, MYC, CCND1, AR, EGF, FOS, and MAPK8, and the possible mechanism is related to the MAPK signaling pathway. SC-FL can regulate the MAPK pathway and affect the expression of Occludin, ZO-1 and connexin 43 to repair damaged BTB and improve spermatogenic dysfunction induced by GTW, which may be one of the possible mechanisms.

Localization of Multidrug Resistance-Associated Proteins along the Blood-Testis Barrier in Rat, Macaque, and Human Testis

The blood-testis barrier (BTB) prevents the entry of many drugs into seminiferous tubules, which can be beneficial for therapy not intended for the testis but may decrease drug efficacy for medications requiring entry to the testis. Previous data have shown that some of the transporters in the multidrug resistance-associated protein (MRP) family (ABCC) are expressed in the testis. By determining the subcellular localization of these transporters, their physiologic function and effect on drug disposition may be better predicted. Using immunohistochemistry (IHC), we determined the site of expression of the MRP transporters expressed in the testis, namely, MRP1, MRP4, MRP5, and MRP8, from immature and mature rats, rhesus macaques, and adult humans. We determined that in all species MRP1 was restricted to the basolateral membrane of Sertoli cells, MRP5 is located in Leydig cells, and MRP8 is located in round spermatids, whereas MRP4 showed species-specific localization. MRP4 is expressed on the basolateral membrane of Sertoli cells in human and nonhuman primates, but on the apical membrane of Sertoli cells in immature and mature rats, representing a potential caution when using rat models as a means for studying drug disposition across the BTB. These data suggest that MRP1 may limit drug disposition into seminiferous tubules, as may MRP4 in human and nonhuman primates but not in rats. These data also suggest that MRP5 and MRP8 may not have a major impact on the penetration of drugs across the BTB.

Testosterone upregulation of tissue type plasminogen activator expression in Sertoli cells

Our previous studies have demonstrated that tissue type plasminogen activator (tPA) might be involved in matrix degradation of blood-testis barrier in rat. In this study, we have further investigated the effect of testosterone (T) on tPA production in rat Sertoli cells. Our results showed that Sertoli cells isolated from rat testes at various ages in vitro secreted tPA in an age-dependent manner. The tPA activity was detected on day 20 after birth, and reached maximum on day 60. The Sertoli cells isolated from the testes on day 20 were then cultured in the presence or absence of testosterone, FSH, and forskolin, the tPA activities were upregulated by T, FSH and forskolin. Addition of H89 or U0126, both inhibited the testosterone-, FSH-, and forskolin-induced tPA expression. It is suggested that FSH- and testosterone-stimulated tPA expression in Sertoli cells may be via PKA and ERK signal transduction. Furthermore, we have observed that testosterone stimulated tPA secretion at all the stages of spermatogenesis (II-VI, VII-VIII, IX-XII and XIII-I), the highest stimulation of tPA activity was observed at stages VII-VIII. This study further suggests that testosterone-induced tPA activity in the Sertoli cells might be related to the function of blood-testis barrier opening and/or closing.

Effect of efferent duct ligation on the function of the blood-testis barrier in rats

The function of the blood-testis barrier has been assessed from the ratio of the Cr-EDTA space in the parenchyma to the measured interstitial volume in the testes of rats at various times after unilateral ligation of the efferent ducts. The barrier remained effective during the phase of fluid accumulation and testicular mass gain, which was linear for at least 24 h, but the testis mass began to decrease between 32 and 40 h after efferent duct ligation, and the Cr-EDTA space at 40 and 48 h after efferent duct ligation exceeded the volume of the interstitial tissue. This finding indicated that, at these times, the barrier to Cr-EDTA, which is normally excluded from the tubules, had broken down and the marker was entering the tubules. Thereafter, the Cr-EDTA space decreased again to be less than the interstitial tissue volume, indicating a restoration of the barrier function, although degeneration of the seminiferous epithelium continued to become more obvious. The present study is the first report of a reversible breakdown of the barrier, but the relevance of the breakdown to the effects on spermatogenesis requires further study.

Effect of efferent duct ligation on the function of the blood-testis barrier in rats.

The function of the blood-testis barrier has been assessed from the ratio of the Cr-EDTA space in the parenchyma to the measured interstitial volume in the testes of rats at various times after unilateral ligation of the efferent ducts. The barrier remained effective during the phase of fluid accumulation and testicular mass gain, which was linear for at least 24 h, but the testis mass began to decrease between 32 and 40 h after efferent duct ligation, and the Cr-EDTA space at 40 and 48 h after efferent duct ligation exceeded the volume of the interstitial tissue. This finding indicated that, at these times, the barrier to Cr-EDTA, which is normally excluded from the tubules, had broken down and the marker was entering the tubules. Thereafter, the Cr-EDTA space decreased again to be less than the interstitial tissue volume, indicating a restoration of the barrier function, although degeneration of the seminiferous epithelium continued to become more obvious. The present study is the first report of a reversible breakdown of the barrier, but the relevance of the breakdown to the effects on spermatogenesis requires further study.

Confocal analysis of the blood-testis barrier in rat and mouse testes

Confocal analysis of the blood-testis barrier in rat and mouse testes

The entry of gossypol across the blood-testis barrier in rats

This paper presents the experimental data about how different formulations of gossypol enter the blood-testis barrier following intravenous administration in acute experiments on rats. It was found that gossypol encapsulated by liposomes crossed the blood-testis barrier more readily than free gossypol, without affecting its pharmacokinetic pattern in the circulating blood, suggesting that liposomes may be useful as drug carriers and may facilitate the entry of encapsulated gossypol into the seminiferous tubule from the blood.

Ablation of the blood-testis barrier in rats and guinea pigs by 48/80, a histamine releaser, and cadmium chloride.

When adult male guinea pigs were injected unilaterally intratesticularly with compound 48/80 (1 mg in 0.05 ml saline), their testicular peritubular capillaries were engorged with blood, intratubular edema was present on the ipsilateral side, and the blood-testicular (BT) barrier (measured by the entrance of acriflavin into the seminiferous tubule) was ablated. The contralateral testis, when injected with saline, showed no pathological changes nor a breakdown of the BT barrier. Subcutaneous injection of guinea pigs with cadmium chloride resulted in a more intense intratubular fluorescence than was observed for 48/80-treated animals. The H1 and H2 receptor blockers (diphenhydramine and cimetidine, respectively) reduced the intensity of capillary engorgement and edema. Intraperitoneal injections of 48/80 (0.5 mg) was lethal to rats, and both diphenhydramine and cimetidine induced survival even with as much as 1 mg of 48/80. Intratubular fluorescence was less severe than that observed for similarly treated guinea pigs or from cadmium chloride-treated rat testes. Neither treatment (48/80 or cadmium chloride) altered the blood-epididymal barrier of either guinea pigs or rats. Species differences were observed in the lethal effects of exogenously administered histamine.

Changes in the ultrastructure of components of the blood-testis barrier in circulatory hypoxia

Changes in the ultrastructure of the blood-testis barrier in rats 30 and 60 min and 1 and 30 days after ligation of the testicular artery were studied by electron microscopy. The results showed that blocking of the blood flow to the testis causes rapidly progressive changes in all components of the blood-testis barrier. Micropinocytosis and destructive changes increase in the cytoplasm of the endotheliocytes of the capillaries, ending in microclasmatosis. The tunica propria of the seminiferous tubules is highly sensitive to ischemia. It becomes thickened, the nuclei and cytoplasmic organoids of its cellular components are deformed, and folding and infiltration of the basement membrane increase. Vacuolation of the cytoplasm of the sustentocytes is accompanied by destruction of the cell membrane and by separation of the sustentocytes from the tunica propria of the tubules.

Proceedings: Studies on some effects of temperature on the blood-testis barrier in rats.

Proceedings: Studies on some effects of temperature on the blood-testis barrier in rats.