An enhanced model for environmental dry eye: Exploring pathological features and underlying factors.

This study aimed to develop an enhanced environmental dry eye (EDE) model that accurately reproduces the etiology of prolonged visual fatigue and investigates the underlying pathological features. A total of 40 adult SPF-grade Wistar rats were randomly assigned to control (n = 20) and model (n = 20) groups. Rats in the control group were maintained under normal conditions, while rats in the model group were exposed to a controlled frontal airflow of 2-4 m/s from a fan for 7.5 h daily while placed on a suspended cylindrical wire mesh frame. Various assessments were performed at different time points during the 14-day experiment, including blink frequency, tear secretion (phenol red thread test), tear film breakup time (BUT), fluorescein staining (FL), corneal epithelial status (light microscopy), ultrastructure of corneal epithelial cells (electron microscopy), and expression levels of inflammatory cytokines (IL-1ß, TNF-α) in tears (enzyme-linked immunosorbent assay). Additionally, mRNA and protein expression levels of MMP-9, IL1ß, IL6, TNF-α, IFN-γ, and caspase-3 in corneal tissues were quantified (real-time quantitative PCR and Western blotting). Compared to the control group, the model group rats exhibited significant decreases in blink frequency (P < 0.001), tear secretion (Schirmer I test) values (P < 0.001), and tear film breakup time levels (P < 0.001). There was also a significant increase in fluorescein staining scores (P < 0.001) in the model group. Histological examination revealed distinct differences of the corneal epithelium between groups. The corneal epithelium of the model group appeared thicker, with disorganized cell arrangement in the superficial and basal layers, partial defects or detachment of superficial epithelial cells, and a rough, uneven surface. Scanning electron microscopy observations showed a rough corneal epithelial surface with numerous cracks and scattered vesicular-like structures in the model group. Furthermore, the model group rats exhibited a significant increase in expression of IL-1ß and TNF-α in tears (P < 0.001), and upregulated expression levels of MMP-9, TNF-α, IL-1ß, caspase-3, IL-6, and IFN-γ at both the mRNA and protein levels in corneal tissues (P < 0.001). In conclusion, the modified "wire-meshing cylindrical board" model effectively overcomes the limitations of the traditional "jogging board " dry eye model and successfully simulates the etiology of prolonged visual fatigue. This innovative EDE model demonstrates a high degree of relevance to dry eye conditions resulting from prolonged visual tasks, with a high success rate of model induction. Moreover, it proves to be a simple, practical, and easily replicable model, making it highly suitable for further studies on prolonged visual fatigue and facilitating its widespread adoption in research and clinical applications.

Electroacupuncture Promotes Motor Function Recovery in MCAO/R Rats by Activating Astrocyte-Related PI3K/AKT Pathway.

Background: Electroacupuncture (EA) is a widely used traditional Chinese medicine method to manage various diseases, including cerebral ischemia-reperfusion injury (CIRI). Objectives: We assessed the neuroprotective effects of EA and examined its mechanism in a rat model of the middle cerebral artery occlusion-reperfusion (MCAO/R). The gait analysis was performed to evaluate the neuroprotective effects. Western blot and immunohistochemistry assays were carried out to determine the molecular mechanisms of EA. Methods: Male SD rats were randomly divided into the sham operation group, right MCAO/R group, and EA group. EA was administered every day (4/20 Hz, 10 min/1 d) at the following acupoints: Baihui (DU20), Yintang (EX-HN3), and Zusanli (ST36). Gait and motor function were analyzed from day 8 onward. Results: The plantar support and balance coordination of MCAO/R rats decreased, and the cellular structure of the ischemic penumbra was unclear. EA improved the gait dynamics of the rats, adjusted the cell structure, further activated astrocytes, and increased the expression and phosphorylation of phosphoinositide 3-kinase/protein kinase B (PI3K/PKB or AKT). Conclusion: EA promoted astrocyte-related effects in the rat model. Our findings suggest that the neuroprotective mechanism of EA may be related to the activation of the PI3K/AKT signaling pathway. The intervention enhanced brain protection and improved motor functions.