ABSTRACT
Objective@#Functional near infrared spectroscopy (fNIRS) was used to assess brain oxygenated hemoglobin (Oxy Hb) activation in college students with different sleep quality under the verbal fluency task (VFT), so as to better provide a theoretical basis for the neural mechanism for sleep quality improvement of college students.@*Methods@#A simple random sampling method was used to investigate 96 college students from one university during 2020 and 2021. According to the results of the Pittsburgh Sleep Quality Index(PSQI), participants were divided into 3 groups: good sleep quality group( n =45), moderate group( n =33), and poor group( n =18). The 53 channel near infrared spectroscopy to collect cerebral blood oxygen signals under the VFT task. Association between oxygenated hemoglobin with sleep quality was analyzed.@*Results@#About 18.75% of college students reported sleep quality problems, including long sleep latency (0.97±0.97) and poor subjective sleep quality (0.96±0.72). There was a significant negative correlation between PSQI score and average oxygenated hemoglobin (Avg HbO) index of dorsolateral prefrontal lobe ( r =-0.23, P =0.03). The Avg HbO index differed significantly between good and poor sleep quality groups on dorsolateral prefrontal lobe( P =0.05).@*Conclusion@#This study verified that there is a positive correlation between sleep quality and cognitive ability among college students. The fNIRS technique could accurately collect blood oxygen signals from dorsolateral prefrontal lobe during cognitive tasks, which proves to be an effective tool for identifying sleep quality of college students.
ABSTRACT
Objective To investigate the effects of lipopolysaccharide(LPS) on myelin phagocytosis during Wallerian degeneration after early peripheral nerve injury in rats.Methods Fifty male Wistar rats were recruited and randomly divided into LPS group(n=20),model group(n=20) and sham group(n=10).The right sciatic nerves of rats in the LPS and model groups were cut and sutured end-to-end,while the sciatic nerve of sham group rats were only exposed.Immediately after surgery,the rats in LPS group were given microinjections of LPS(2 g/L) into the surgical site in a final volume of 1 μL,and the rats in other two groups were injected with the same volume of saline.The sciatic nerves were taken at 1.5 h,24 h and 7d after surgery.Real-time quantitative PCR(qRT-PCR) was applied to detect the dynamic expressions of IL-1β mRNA and MCP-1 mRNA.Immunofluorescence staining was used to test the expression of CD68+ macrophages in sciatic nerves.HE staining was used to observe the pathological alterations of sciatic nerves tissue.ORO staining was used to observe sciatic nerves demyelination.LFB staining was used to detect the sciatic nerves myelin.Sciatic function index was used to evaluate the recovery of motor function in rats.Results Compared with the model group,qRT-PCR indicated that the expression of IL-1β and MCP-1 from LPS group were increased at 1.5 h and 24 h after surgery(P<0.001, P<0.001),respectively.Compared with the model group,the expression of CD68+ cells was increased significantly at 7th day after surgery(P<0.05).Histological examination showed that compared with the model group,a lot of inflammatory cells and Schwann cells were found at sciatic nerve stump in the LPS group at 7th day after operation.ORO staining showed that the degree of demyelination in the LPS group was higher than that in the model group.LFB staining showed that the sciatic nerve stump demyelination appeared in both model group and the LPS group at 7th day after operation,but compared with the model group,myelin debris clearance in the LPS group was significantly accelerated(P<0.05).Finally,compared with the model group,the SFI in the LPS group was increased significantly at 20 d after surgery(P<0.05).Conclusions The results confirm that LPS is possible to manipulate the innate immune response to accelerate myelin clearance during Wallerian degeneration after early peripheral nerve injury in rats.
ABSTRACT
BACKGROUND:The mechanism underlying Wal erian degeneration fol owing peripheral nerve injury is complex. Immune regulation on Wal erian degeneration is beneficial for early repair of perpheral nerve injury. OBJECTIVE:To investigate the effects of Tol-like receptor 4 (TLR4) antagonist on Wal erian degeneration and axonal regeneration after early peripheral nerve injury in rats. METHODS:Fifty male Wistar rats were recruited and randomly divided into treatment group (n=20), model group (n=20) and sham group (n=10). The right sciatic nerves of rats in treatment and model groups were cut and sutured end-to-end, while the sciatic nerves of rats in sham group were only exposed. In the treatment group rats were intravenously injected with 0.15 mg/kg TAK-242 via tail vein 1 hour preoperatively and 7 days postoperatively, and the rats in the other two groups were given intravenous injection of the same volume of normal saline. The sciatic nerves were removed at 24 hours, 3, 4 and 7 days after surgery. RESULTS AND CONCLUSION:Real-time PCR indicated that the mRNA expressions of interleukin-1βand monocyte chemoattractant-1 were significantly increased in the model group compared with the sham group at 24 hours after surgery (both P<0.001), while the expressions were significantly decreased after TAK-242 injection (both P<0.001). Immunofluorescence showed that compared with the model group, down-regulated expression of CD68+and iba1+cel s appeared in the treatment group at 3 days after surgery (P<0.01, P<0.05). Luxol fast blue staining revealed that demyelination at the sciatic nerve stump appeared in both model and treatment groups at postoperative 7 days, but myelin debris clearance in the treatment group was significantly reduced compared with the model group (P<0.05). Hematoxylin-eosin staining showed that a lot of inflammatory cel s, Schwann cells and regenerated nerve fibers at the sciatic nerve stump were found in the model group, while there were few inflammatory cells, Schwann cel s and regenerated nerve fibers in the treatment group at 7 days after surgery. Immunohistochemistry found that the expression of growth-associated protein-43 in the treatment group was significantly lower than that in the model group at 4 days postoperatively (P<0.05). Besides, compared with the model group, a significantly decreased sciatic functional index was found in the treatment group at 20, 30 and 40 days after surgery (P<0.05). These results show that TLR4 antagonists delay early nerve regeneration in rats after sciatic nerve injury probably by inhibiting the TLR4 signaling pathway.