Peer victimization and non-suicidal self-injury among high school students: the mediating role of social anxiety, mobile phone addiction, and sex differences.

BACKGROUND: Peer victimization (PV) is one of the major causes of non-suicidal self-injury. Non-suicidal self-injury (NSSI), peer victimization, social anxiety, and mobile phone addiction are significantly related; however, the interaction mechanism and effect of sex differences remain to be determined. OBJECTIVE: Herein, we investigated the relationship between peer victimization and NSSI among Chinese high school students. We also explored the chain mediating roles of social anxiety and mobile phone addiction and the regulatory role of sex. The findings of this study provide insights for theoretical interventions based on internal mechanisms. METHOD: A self-reported survey of 14,666 high school students from Sichuan County was conducted using a peer victimization scale, NSSI scale, social anxiety scale, and mobile phone addiction scale. A self-administered questionnaire was used to capture sociodemographic information. RESULTS: Peer victimization, social anxiety, and mobile phone addiction were positively correlated with NSSI. Peer victimization had significant direct predictive effects on NSSI (95% CI: 0.341, 0.385) and significant indirect predictive effects on NSSI through social anxiety (95% CI: 0.008, 0.019) or mobile phone addiction (95% CI: 0.036, 0.053). Peer victimization had significant indirect predictive effects on NSSI through social anxiety as well as mobile phone addiction (95% CI: 0.009, 0.014). The first stage (predicting the effect of peer victimization on NSSI) and the third stage (predicting the effect of mobile phone addiction on NSSI) were both moderated by sex. CONCLUSIONS: Peer victimization could directly predict NSSI and indirectly predict NSSI through social anxiety and mobile phone addiction. Thus, social anxiety and mobile phone addiction exhibited chain mediating effects between peer victimization and NSSI in high school students; moreover, sex might be involved in the regulation of the mediation process.

Proangiogenic functions of osteopontin-derived synthetic peptide RSKSKKFRR in endothelial cells and postischemic brain.

OBJECTIVE: The aim of this study was to investigate the potential therapeutic effects of a newly discovered osteopontin-derived synthetic peptide "RSKKFRR" in a rat model of ischemic stroke. METHODS: A total of 24 male SD rats were randomly divided into three groups. The model of ischemic stroke was made up of the middle cerebral artery occlusion (MACO). The rats were divided into sham operation group (Sham), control group (MACO + PBS) and treatment group (MACO + OPNpt9), eight rats in each group. In the control group and the treatment group, PBS or OPNpt9 was injected into the nasal cavity after MACO once a day, and the area of new blood vessels and the recovery of nerve function were observed 14 days later. Whether the proliferation, migration and tube formation of HUVECs were promoted by OPNpt9 was tested. The expression levels of related proangiogenic factors were also detected. RESULTS: OPNpt9 was found to contribute to cerebral microvascular remodeling and neurological improvement in ischemic rats while promoting endothelial cell migration, proliferation and tube formation in vitro. These effects were mediated by activation of the p-ERK/MMP-9/VEGF pathway. CONCLUSION: In conclusion, OPNpt9 promotes angiogenesis and neurological recovery after ischemic stroke.