Cysteine supplementation pre-freeze and post-thaw improves integrity and reduces oxidative stress in cryopreserved ram spermatozoa.

Cryopreserved ram sperm is highly sensitive to oxidative stress by reactive oxygen species (ROS) which impair sperm function and integrity. Antioxidants such as cysteine can mitigate the effect of ROS, although the optimal concentration or timing of supplementation is unknown. This study aimed to determine the effect of concentration and timing of cysteine supplementation on the integrity and function of cryopreserved ram spermatozoa. Nine ejaculates were collected from three Texel rams then cryopreserved and supplemented with cysteine (0, 0.5, or 1.0 mg/mL) added pre-freeze (PF), post-thaw (PT) or pre-freeze and post-thaw (PF + PT) generating seven treatments: 1) control 0 mg/mL, 2) PF 0.5 mg/mL, 3) PF 1 mg/mL, 4) PT 0.5 mg/mL, 5), PT 1.0 mg/mL, 6) PF + PT 0.5 mg/mL and 7) PF + PT 1.0 mg/mL. Sperm motility, viability, acrosome integrity, ROS production and penetrability through artificial cervical mucus were assessed post-thaw. Cysteine supplementation reduced ROS production which thereby improved spermatozoa motility, viability, acrosome integrity and penetrability (p < 0.001) Sperm integrity for all parameters was greatest in spermatozoa treated PF + PT with 1.0 mg/mL cysteine, although treatment pre-freeze or post-thaw also improved integrity beyond the control. This study has identified that 1.0 mg/mL cysteine is most beneficial and has highlighted the importance of preventing oxidative stress in spermatozoa post-thaw. These finding can help to mitigate the detrimental effect of cryopreservation on spermatozoa and aid the development of cryopreservation protocols in sheep.

Prevalence of insomnia among university students in South Asian Region: a systematic review of studies.

INTRODUCTION: Insomnia is a global health problem among university students which is associated with various psychiatric problems like depression and anxiety. While different developed and developing countries assessed the prevalence of insomnia in youth, currently there is hardly systematic review of studies found based on the prevalence of insomnia in South Asia. AIMS: The aim of this study is to systematically review the evidence relating to the prevalence rate of insomnia in university students in South Asian countries. METHODS: Electronic searches of three databases, PubMed, Cochrane library, and Worldwide science were performed from 2010 to 2020 before April. In total, seven studies were included for evaluating insomnia in South Asian region among university students. RESULTS: The prevalence rates of insomnia of the seven studies ranged between 35.4% (95% CI: 32.4-38.5%) and 70% (95% CI: 65.7-74.1%). The pooled prevalence of insomnia among university students was 52.1% (95% CI: 41.1-63.1%). CONCLUSIONS: This review emphasized that insomnia in university students might be a common health issue to give full concentration in their studies and academic performance. Thus, more attention should be given to the determinants of insomnia among university students, so that it could be helpful to identify the main causes of insomnia and effective measures could be taken.