Effects of intratesticular injection of hypertonic mannitol and saline on the quality of donkey sperm, indicators of oxidative stress and testicular tissue pathology

OBJECTIVES

The aim of the present study was to examine donkey sperm quality after intratesticular injection of hypertonic mannitol (HM) and saline (HS).

METHODS

Randomly assigned to five treatment groups were 15 adult male donkeys: (1) Control group (no treatment), (2) Surgery group (surgical castration for testosterone control), (3) NS group (normal saline intratesticular injection), (4) HS group (hypertonic saline), and (5) HM group. We injected 20 mL per testicle. We took 5 mL blood from all donkeys before injection. Castration was performed under general anesthesia 60 days later. Samples included blood and testicular tissue. Total motility (TM), progressive motility (PM), movementy features, DNA damage, morphology, viability, and plasma membrane functionality were evaluated. Hormone analyses, histomorphometric studies and oxidative stress indices including total antioxidant capacity (TAC), glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and NADP+/NADPH were evaluated. Apoptosis, pyroptosis-related Bax, Caspase-1, GSDMD, and Bcl-2 expression were also assessed.

RESULTS

In HS and HM groups, testosterone, epididymal sperm count, motility, viability, and plasma membrane functionality dropped while sperm DNA damage increased. HS and HM groups had significantly lower histomorphometric parameters, TAC, GPx, SOD, GSH, and Bcl-2 gene expression. MDA, NADP+/NADPH, Bax, Caspase-1, and GSDMD gene expression were substantially higher in the HS and HM groups than in the control group.

CONCLUSIONS

Toxic effects of hypertonic saline and mannitol on reproductive parameters were seen following, hence, they might be considered as a good chemical sterilizing treatment in donkeys.

Development of a new sterilization method for microalgae media using calcium hypochlorite as the sterilant

Calcium hypochlorite (Ca(ClO)2), which can be stably stored in powder form for a long period, is widely used as a disinfectant in various fields. A new sterilization process was developed in the present study, where a microalgal medium was sterilized using 0.02% Ca(ClO)2, followed by complete neutralization of the Ca(ClO)2 within 8 h through catalytic reaction of an MnCl2-Na2EDTA complex and a synergistic effect of glucose. When comparing the growth of Chlorella vulgaris in the autoclaved medium, a 2.65 times greater maximum cell growth was observed in cells grown in the medium prepared by treatment of Ca(ClO)2. This result indicates that denaturation of the medium by heat can hinder the growth of some microorganisms. In the case of cultivation of Euglena gracilis, successful culture growth was achieved without growth inhibition or contamination on a medium prepared in the same manner.

Growth medium sterilization using decomposition of peracetic acid for more cost-efficient production of omega-3 fatty acids by Aurantiochytrium

Aurantiochytrium can produce significant amounts of omega-3 fatty acids, specifically docosahexaenoic acid and docosapentaenoic acid. Use of a glucose-based medium for heterotrophic growth is needed to achieve a high growth rate and production of abundant lipids. However, heat sterilization for reliable cultivation is not appropriate to heat-sensitive materials and causes a conversion of glucose via browning (Maillard) reactions. Thus, the present study investigated the use of a direct degradation of Peracetic acid (PAA) for omega-3 production by Aurantiochytrium. Polymer-based bioreactor and glucose-containing media were chemically co-sterilized by 0.04% PAA and neutralized through a reaction with ferric ion (III) in HEPES buffer. Mono-cultivation was achieved without the need for washing steps and filtration, thereby avoiding the heat-induced degradation and dehydration of glucose. Use of chemically sterilized and neutralized medium, rather than heat-sterilized medium, led to a twofold faster growth rate and greater productivity of omega-3 fatty acids.

Changes in blood testosterone concentrations after surgical and chemical sterilization of male free-roaming dogs in southern Chile

There is a growing interest in chemical sterilization as an alternative to surgical castration in large-scale sterilization campaigns to control canine populations. An important step toward understanding the short-term and long-term effects of chemical sterilants is to determine their impact on blood testosterone concentrations, particularly as these could influence dog behavior after treatment. A field trial was conducted with 118 free-roaming male dogs in the Chilean Patagonia, where 36 dogs were chemically sterilized using EsterilSol, 39 dogs were surgically castrated, and 43 dogs remained intact as controls. Blood testosterone levels were determined at four time periods: on enrollment 6 months before treatment (t-6m), at the time of treatment (t0, within one hour after surgical castration or chemical sterilization and during a concurrent 2-week period for the control group), four (t+4m), and six (t+6m) months after treatment. Intrinsic and temporal factors were evaluated; age was significantly associated with testosterone, where dogs 2- to 4-year-old had the highest testosterone concentrations (P = 0.036), whereas body weight and body condition scores were not associated with testosterone; testosterone concentration was not influenced by time of day, month, or season. After treatment (t+4m and t+6m), all of the surgically castrated dogs had testosterone concentrations below 1.0 ng/mL. On the basis of this cut point (<1 ng/mL), testosterone remained unchanged in 66% of the chemically sterilized dogs at both t+4m and t+6m; it remained low for 22% of dogs at both t+4m and t+6m; it was unchanged at t+4m but low at t+6m in 9% of dogs; and, it was low at t+4m but reverted back to unchanged at t+6m in one dog (3%). Incidentally, testosterone in chemically sterilized dogs increased dramatically within 1 hour of treatment (t0), more than doubling (131%) the concentration of control dogs at the time of treatment (t0), likely because of severe necrosis of interstitial cells. The use of EsterilSol as a method of sterilizing dogs had a variable effect on blood testosterone concentrations. Approximately, 30% of chemically sterilized dogs had a reduced testosterone concentration (actual maximum, 1 ng/mL) after 6 months, similar to that of surgically castrated dogs. Most chemically sterilized dogs, however, showed no long-term changes in blood testosterone concentrations.