Effect of seasonal infertility period on boar sperm proteins and quality characteristics

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗSwine seasonal infertility reduces the productivity and profitability of a pig farm. The main causes of this condition are elevated environmental temperatures and long photoperiod during the summer season. The aim of this study was to investigate which sperm proteins and parameters are affected during the period of seasonal infertility. Depending on the environmental temperatures, the period from October to June was considered as cold and the period from July to September as warm season. A total of 65 ejaculates from 18 boars were collected over a year. Each semen sample was evaluated for kinetics (Computer Assisted Semen Analyzer), morphology (Sperm Blue stain), viability (Propidium Iodide - Calcein AM stain), mitochondrial membrane potential (Rhodamine 123 – Propidium Iodide stain), membrane integrity and functionality (Hypo-osmotic swelling test) and sperm DNA integrity (Acridine Orange Test). Moreover, selected proteins (HSP90, GPX5, OPN) were detected and quantified. The kinetic parameters VSL, LIN and the midpiece abnormalities were significantly higher in the warm compared to the cold season (p<0.05), while a strong tendency towards higher values for HSP90 and GPX5 was observed in warm compared to cold season (p=0.07and p=0.06, respectively). In conclusion, among the boar sperm characteristics tested in our study, seasonal infertility period negatively affected VSL and LIN kinetics, while GPX5 seminal plasma enzyme and HSP90 sperm surface protein increased their sperm protective effects

The effect of dexamethasone on tissue fibrinolytic system in male and female rats

Background: Dexamethasone in low and high doses affects blood fibrinolytic activity both in animals and humans. In this study the effect of a high dose of dexamethasone on plasminogen activator activity (PAA), t-PA antigen level, plasminogen activator inhibition (PAI) and plasmin inhibition (Pl) in rat heal?, brain, liver, lungs and kidneys was investigated in both sexes. Materials and Methods: Twenty male and twenty female adult Wistar rats were used. Dexamethasone was administered as a single intraperitoneal injection (3mg/kg/day) in rats, once daily, for a period of 5 consecutive days. t-PA antigen level was assayed by an enzyme-linked immunoabsorbant assay method PAA, PAI and PI were determined by spectrophotometric methods. The plasminogen used was isolated from I at plasma. Results: Dexamethasone induced variable changes in the fibrinolytic parameters in mt heart, brain and liver of both sexes; in lungs and kidneys dexamethasone had no effect. Conclusion: These changes of PAA, PAI and t-PA antigen level in heart, brain and liver induced by dexamethasone might be of importance regarding the involvement of glucocorticoids and plasminogen activators/plasmin in many pathophysiological conditions

Gossypol-induced inhibition of plasminogen activator activity in human and ovine acrosomal extract

The effect of gossypol-a polycyclic compound isolated from cotton seeds-on the plasminogen activator activity of man and ram acrosomal extracts was explored in vitro. The action of gossypol on the plasminogen activator activity was investigated by a spectrophotometric method using the chromogenic substrate S-2251. Gossypol, a known antispermatogenic agent, was found to effectively inhibit human and ovine acrosomal plasminogen activator activity. The inhibition was dose-dependent. Plasminogen activator activity from man and ram extracts was completely inhibited by 350 mu mol l(-1) and 300 mu mol l(-1) of gossypol, respectively. In additional experiments, low, non-spermicidal concentrations of gossypol (2.5-40 mu mol l(-1)) were found to significantly inhibit plasmin activity in a dose-dependent manner. The results suggest that inhibition of both acrosomal plasminogen activator and plasmin activity is a possible mechanism by which gossypol exerts its antifertility effect, since the plasminogen activator/plasmin system plays a role in the whole process of ovum fertilization

Inhibition of human and ovine acrosomal enzymes by tannic acid in vitro

The effect of tannic acid, a common flavonoid, on the acrosin and plasminogen activator activity and plasmin activity of human and ram spermatozoa was evaluated. Acrosin and plasminogen activator activity were determined by spectrophotometry using the chromogenic substrates N-alpha -benzoyl-DL-arginine para-nitroanilide-HCl (BAPNA) and H-D-valy-L-leucyl-L-lysine-p-nitroanilide -2HCI (S-2251), respectively. In extracts from both human and ovine acrosomes, the activities of acrosin and plasminogen activators were susceptible to tannic acid inhibition. The inhibitory effect of tannic acid was observed at concentrations > 50 mu mol l(-1) in a dose-dependent manner, in additional experiments, low concentrations of tannic acid significantly inhibited tissue-type plasminogen activator, urokinase-type plasminogen activator and plasmin activity in a concentration-dependent manner over the range 0.25-200 mu mol l(-1). Tannic acid reduced the motility of ram spermatozoa at a concentration of 1000 mu mol l(-1) after 2 and 3 h co-incubation with spermatozoa. The motility of human spermatozoa remained unchanged over the range 0.1-1000 mu mol tannic acid l(-1) during 3 h co-incubation. These results indicate that tannic acid inhibited the activity of both acrosin and plasminogen activator and indicates a possible mechanism by which flavonoids exert their antifertility effects