Toxicity and Mutagenicity Evaluation Following RISUG Contraception Reversal in Rats.

Reestablishment of fertility, after a male contraceptive method, is of great concern. In this context, RISUG (Reversible Inhibition of Sperm Under Guidance) has been evaluated for its mutagenicity following reversibility with dimethyl sulfoxide (DMSO)/sodium bicarbonate (NaHCO3) in Wistar albino rats. Animals were divided into 7 groups, namely, sham-operated control, vas occlusion with RISUG for 90 and 360 days, reversal with DMSO and NaHCO3 after 90 and 360 days, respectively. The testis, cauda epididymis, cauda epididymal spermatozoa, and serum were evaluated for apoptosis and hormonal status through various assays. RISUG was subjected to Ames test at dose levels of 10, 50, and 100 µL. Results of terminal deoxynucleotidyl transferase nick end labeling and caspase-3 assays in testes and cauda epididymis revealed that the percentage of positive cells in the experimental groups was comparable to sham-operated control. Annexin V assay in cauda epididymal spermatozoa showed slight elevation in group II ( P < 0.05), whereas in the remaining groups, minimum numbers of positive sperms were found. Hormone profile, namely, testosterone, prolactin, cortisol, prostate-specific antigen, and sperm antibody concentration, remained unchanged. In Ames test, no significant increase was observed in the number of revertant colonies on plates containing RISUG in the presence and absence of S9 mix in all 3 strains. Therefore, the reversal of RISUG-induced contraception by solvent vehicle DMSO/NaHCO3 was successful without any toxicity at the cellular levels.

Abundance of antibiotic resistance genes in environmental bacteriophages.

The ecosystem is continuously exposed to a wide variety of antimicrobials through waste effluents, agricultural run-offs and animal-related and anthropogenic activities, which contribute to the spread of antibiotic resistance genes (ARGs). The contamination of ecosystems with ARGs may create increased opportunities for their transfer to naive microbes and eventually lead to entry into the human food chain. Transduction is a significant mechanism of horizontal gene transfer in natural environments, which has traditionally been underestimated as compared to transformation. We explored the presence of ARGs in environmental bacteriophages in order to recognize their contribution in the spread of ARGs in environmental settings. Bacteriophages were isolated against environmental bacterial isolates, purified and bulk cultured. They were characterized, and detection of ARG and intI genes including blaTEM, blaOXA-2, intI1, intI2, intI3, tetA and tetW was carried out by PCR. This study revealed the presence of various genes [tetA (12.7 %), intI1 (10.9 %), intI2 (10.9 %), intI3 (9.1 %), tetW (9.1 %) and blaOXA-2 (3.6 %)] and blaTEM in a significantly higher proportion (30.9 %). blaSHV, blaOXA-1, tetO, tetB, tetG, tetM and tetS were not detected in any of the phages. Soil phages were the most versatile in terms of ARG carriage. Also, the relative abundance of tetA differed significantly vis-à-vis source. The phages from organized farms showed varied ARGs as compared to the unorganized sector, although blaTEM ARG incidences did not differ significantly. The study reflects on the role of phages in dissemination of ARGs in environmental reservoirs, which may provide an early warning system for future clinically relevant resistance mechanisms.

Studies on biochemical, oxidative and genotoxicity alterations following vas blockage with reversible inhibition of sperm under guidance and reversal in rats.

CONTEXT: Vas obstruction with reversible inhibition of sperm under guidance (RISUG) for contraception and its reversal, may cause oxidative stress or inimical effects on male reproductive functions. OBJECTIVE: To evaluate the biochemical and genotoxicity at the level of reactive oxygen species (ROS) following vas occlusion with RISUG and its reversal by Dimethyl sulphoxide (DMSO) and 5% NaHCO3 in Wistar albino rats. SETTINGS AND DESIGN: Animals were divided into seven groups (n = 10), namely sham-operated control, short-term vas occlusion with RISUG for 90 days, reversal with DMSO and 5% NaHCO3, long-term vas occlusion with RISUG for 360 days, reversal with DMSO and 5% NaHCO3. MATERIALS AND METHODS: Biochemical markers in reproductive tissues, hematology, serum biochemistry, serum electrolytes and ROS measuring indicators, e.g., lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase were examined. STATISTICAL ANALYSIS USED: One-way analysis of variance test was performed for analyses of data obtained in this study using the SPSS 10.0 software (SPSS Inc., Chicago, IL, USA). RESULTS: The tissue and clinical chemistry did not show appreciable alterations in RISUG injected and reversal Groups (II-VII) as compared to sham control. The genotoxicity and various ROS markers fluctuated within control limits following short- and long-term vas occlusion and reversal. CONCLUSIONS: The study suggested that the reversal procedures, following RISUG contraception, were not associated with any kind of toxicological manifestations.