Contraceptive effect of sperm-agglutinating factor isolated from Staphylococcus aureus in mouse

Bacteriospermia - A formidable player in male subfertility

Bacterial colonization of male reproductive tissues, cells, and fluids, and the subsequent impact of bacteria on the sperm architecture, activity, and fertilizing potential, has recently gained increased attention from the medical and scientific community. Current evidence strongly emphasizes the fact that the presence of bacteria in semen may have dire consequences on the resulting male fertility. Nevertheless, the molecular basis underlying bacteriospermia-associated suboptimal semen quality is sophisticated, multifactorial, and still needs further understanding. Bacterial adhesion and subsequent sperm agglutination and immobilization represent the most direct pathway of sperm-bacterial interactions. Furthermore, the release of bacterial toxins and leukocytic infiltration, associated with a massive outburst of reactive oxygen species, have been repeatedly associated with sperm dysfunction in bacteria-infested semen. This review serves as a summary of the present knowledge on bacteriospermia-associated male subfertility. Furthermore, we strived to outline the currently available methods for assessing bacterial profiles in semen and to outline the most promising strategies for the prevention and/or management of bacteriospermia in practice.

Biocompatible polyvinyl alcohol and RISUG® blend polymeric films with spermicidal potential

Majority of the commercially available vaginal contraceptives encompasses cervicovaginal membrane disrupting detergent molecules as pharmacologically active ingredients. Development of a tissue-compatible vaginal contraceptive agent is necessary to circumvent the existing demand for female contraception in the reproductive healthcare sector. With this objective, the present study delineates the use of RISUG^® based non-hormonal female contraceptive films. RISUG^® was blended with polyvinyl alcohol (PVOH) to formulate biodegradable intra-vaginal contraceptive films. The formulated films were characterized for their thermal, physiochemical and biological features. The results showed that both RISUG^® and PVOH were miscible and interacted at the intermolecular level. Variations in the concentration of RISUG^® resulted in the changes in physicochemical, thermal and rheological characteristics of the formulated blends. In vitro toxicological assay of the polymeric formulations did not show any significant toxicity. However, the blend films retained spermicidal potential of RISUG^®. Furthermore, in vivo toxicological evaluation of the polymeric blend in the rat model revealed about their biocompatibility with no significant organ toxicity, hematological and biochemical alterations. These results together confirm the potential applicability of the PVOH:RISUG^® blend films as a vaginal contraceptive.

Escherichia coli recombinant sperm immobilizing factor RecX as a potential vaginal contraceptive

BACKGROUND

To control the overpopulation and unintended pregnancies, vaginal contraceptives have gained recent surge of interest because of its topical application with possible avoidance of systemic effects. However non-specific cytotoxicity associated with detergent-based synthetic vaginal contraceptive agents limits their use and generates considerable interest in the development of vaginal contraceptives of biological origin for controlling reproduction and ultimately growing population. In this study, we have cloned, over-expressed an Escherichia coli gene encoding a sperm immobilizing factor (SIF) that inhibits sperm motility for the development of vaginal contraceptive from a biological source i.e. E. coli. The contraceptive efficacy of the Escherichia coli recombinant sperm immobilizing factor (r-SIF) was also determined.

METHODS

Genomic DNA library of an E. coli strain isolated from semen sample of an infertile male was constructed for the identification and cloning of E. coli SIF coding gene. This gene was sub-cloned in pBADmycHisB for over-expression and the r-SIF was purified using Ni-NTA affinity chromatography. Effect of r-SIF on mouse sperm motility, viability and on morphology was evaluated. Binding of r-SIF to mouse sperm was demonstrated by fluorescent labeling. Contraceptive efficacy of r-SIF was checked in murine model.

RESULTS

Genomic library resulted in five hundred transformants; five clones were found positive for sperm immobilizing activity. The protein product of the insert DNA sequence in one of the transformants showed maximum sperm immobilizing activity. Sequence analysis of ORFs in the insert revealed homology to recX on both nucleotide and protein level. 40 μg of the purified r-SIF showed immediate spermicidal activity in vitro for mouse sperm. Scanning electron micrograph of the r-SIF treated sperm showed intense morphological damage to sperm. FITC labeled r-SIF showed highest fluorescence at the head region of the sperm. 5 μg of purified r-SIF exhibited a complete contraceptive effect in mouse model.

CONCLUSION

r-SIF could be seen as potential target to be developed as potent and safe vaginal contraceptive in future.

Safety studies of sperm agglutinating factor produced by Staphylococcus aureus as a vaginal contraceptive: in vivo studies

Sperm agglutinating factor (SAF) isolated from Staphylococcus aureus when applied at concentration 10 μg before mating completely prevented conception in the mouse. The objective of the present study was to evaluate its safety, as safety is an important concern to be addressed before a compound is selected for contraceptive use. Our results showed that SAF has a very high safety profile. Vaginal application of SAF at 10 μg to the mouse for 14 consecutive days caused no systemic toxicity and vaginal irritation as indicated by lack of effect on organ weights and histology. Moreover, no adverse effect was observed on the subsequent reproductive capability, perinatal outcome and growth and development of the offspring. SAF (10 μg) did not irritate the skin or penile mucosa. Oral administration of 2 mg/kg body weight of SAF did not show any toxicity to reproductive and non-reproductive organs. Therefore, SAF with spermicidal activity and lack of toxicity may have the potential to become the active ingredient of a vaginal contraceptive.