Cellular responses and microRNA profiling in bovine spermatozoa under heat shock

Sperm function is susceptible to adverse environmental conditions. It has been demonstrated that in vivo and in vitro exposure of bovine sperm to elevated temperature reduces sperm motility and fertilizing potential. However, the cascade of functional, cellular and molecular events triggered by elevated temperature in the mature sperm cell remains not fully understood. Therefore, the aim of this study was to determine the effect of heat shock on mature sperm cells. Frozen-thawed Holstein sperm were evaluated immediately after Percoll purification (0 h non-incubation control) or after incubation at 35°C, 38.5°C, and 41°C for 4 h. Heat shock reduced sperm motility after 3 - 4 h at 41°C while mitochondrial activity was reduced by 38.5 and 41°C when compared to the control. Heat shock also increased sperm reactive oxygen species production and caspase activity. Heat-shocked sperm had lower fertilizing ability, which led to diminished cleaved and blastocyst rates. Preimplantation embryo developmental kinetics was also slowed and reduced by sperm heat shock. The microRNA (miR) profiling identified >300 miRs in bovine sperm. Among these, three and seven miRs were exclusively identified in sperm cells exposed to 35 and 41°C, respectively.

Strontium ranelate as a possible disease-modifying osteoarthritis drug: a systematic review

Considering that osteoarthritis (OA) is the most prevalent joint disease worldwide, multiple pharmacological treatments have been proposed to alter the articular structure with potential benefit in the progression of the disease. The so-called disease-modifying OA drugs have been frequently investigated but conclusive findings are rare. Strontium ranelate (SrRan) is a drug usually prescribed to treat osteoporosis, with proven effects in decreasing the risk of fractures and possible effect in reducing the progression of OA. The objective of this review was to demonstrate the current panorama of knowledge on the use of SrRan in clinical and experimental models, clarifying its mechanisms of action and describing possible anti-nociceptive and anti-inflammatory effects. The systematic review was based on the PRISMA statement and included articles that are indexed in scientific databases. Fifteen studies were included: seven pre-clinical and eight clinical studies. Despite the limited number of studies, the results suggest a positive effect of SrRan in patients with OA, through changes in functional capacity and reduction of progression of morphological parameters and joint degradation, with moderate quality of evidence for those clinical outcomes. Novel studies are necessary to elucidate the molecular targets of SrRan, focusing on anti-inflammatory effects and histological changes promoted by SrRan, which seemed to reduce the progression of OA in the experimental and clinical studies.

Effect of strontium ranelate on pain behavior in an experimental model of osteoarthritis

Strontium ranelate (SrRan) is a drug usually prescribed to treat osteoporosis, with proven effects of decreasing the risk of fractures and an indication of reducing the progression of osteoarthritis (OA). This study aimed to investigate the effects of SrRan as either a prophylactic or a treatment drug, using an OA rat model to assess pain behavior. A monoiodoacetate (MIA)-induced knee joint OA model in Wistar rats was used. Thirty Wistar rats (both sexes, 60 days old) were distributed in five groups of 6 rats each: the control group, that received no intervention; a prophylactic group, that received oral administration of 25 mg·kg^-1·day^-1 of SrRan for 28 days before induction of OA; a group treated with 25 mg·kg^-1·day^-1 of SrRan for 28 days after OA induction; a group treated with 50 mg·kg^-1·day^-1 during 28 days after OA induction; and a group that received oral saline for 28 days after induction. The assessment of pain behavior was performed considering articular incapacitation (weight-bearing test), mechanical hyperalgesia (Randall Selitto test) and motor activity (rotarod test), on days 0, 7, 14, 21, and 28. This experiment did not yield a significant difference when comparing the group that received SrRan prophylactically with the groups treated with 25 or 50 mg·kg^-1·day^-1 and the group that received oral saline. Thus, SrRan did not provide analgesia in either treated rats or as a prophylactic drug with the tested doses. Higher doses should be tested further to achieve possible significant results.

The peroxisomal protein import machinery--a case report of transient ubiquitination with a new flavor

The peroxisomal protein import machinery displays remarkable properties. Be it its capacity to accept already folded proteins as substrates, its complex architecture or its energetics, almost every aspect of this machinery seems unique. The list of unusual properties is still growing as shown by the recent finding that one of its central components, Pex5p, is transiently monoubiquitinated at a cysteine residue. However, the data gathered in recent years also suggest that the peroxisomal import machinery is not that exclusive and similarities with p97/Cdc48-mediated processes and with multisubunit RING-E3 ligases are starting to emerge. Here, we discuss these data trying to distill the principles by which this complex machinery operates.