Diabetic retinopathy (DR) is one of the most common and serious complication of diabetes mellitus, which is the main cause of vision loss in adults. Biological clock genes produce circadian rhythms and control its operation, while the disorder of the expression causes the occurrence and development of a series of diseases. It has been demonstrated that biological clock genes might take effects in the development and progression of DR. On the one hand, circadian rhythm disorder-related behavior disrupts the circadian oscillation of clock genes, and the change in its expression level is prone to unbalanced regulation of glucose metabolism, ultimately increasing the risk of type 2 diabetes mellitus and DR pathogenesis. On the other hand, DR patients exhibit symptoms of circadian rhythm disorders, and it has been suggested that the clock genes may control the development and progression of DR by affecting a variety of retinal pathophysiological processes. Therefore, maintaining normal circadian rhythm can be used as a disease prevention strategy, and studying the molecular mechanism of clock genes in DR can provide new ideas for more comprehensive elaboration of the pathogenesis of DR and search for new therapeutic targets.

Objective Mild hypothermia (MHT) can effectively protect the brain in traumatic brain injury (TBI). This study was to investigate the effects of MHT on the calmodulin (CAM) expression and brain edema in the rat model of TBI. Methods Ninety adult SD rats were randomly divided into a sham operation, a normal temperature and an MHT group of equal number. Immediately after TBI, the rats of the MHT group maintained at a rectal temperature of (32 ± 0.5) °C for 6 hours. Modified neurological severity scores (mNSS) were obtained from 6 rats in each group at 1, 3, 5 and 7 days after modeling, and the rest of the animals subjected to brain MRI at 6, 12, 24 and 48 hours and then killed for determination of the CAM gene transcription and protein expression in the brain tissue by real-time PCR, immunohistochemistry and Western blot. Results The mNSSs were significantly higher in the MHT and normal temperature groups than in the sham operation control (P < 0.05) at all time points, neurological severity markedly decreased in the MHT group compared with the normal temperature group (P < 0.05). At 6, 12, 24 and 48 hours, the expression of CAM mRNA was remarkably down-regulated in the MHT group (1.83 ± 0.19, 1.72 ± 0.12, 1.59 ± 0.06 and 1.60 ± 0.07) in comparison with the normal temperature group (2.76 ± 0.25, 2.49 ± 0.18, 2.04 ± 0.14 and 1.65 ± 0.09) (P < 0.05), even lower in the MHT than in the normal temperature group (P < 0.05), but higher in both of the two groups than in the sham operation group (P < 0.05). At 6, 12, 24 and 48 hours, the volume of brain edema was significantly reduced in the MHT group ([32.14 ± 4.52], [36.52 ± 4.10], [42.10 ± 4.38] and [46.25 ± 5.02] mm³) as compared with the normal temperature group ([48.56 ± 5.35], [53.13 ± 6.31], [59.23 ± 6.82] and [62.35 ± 7.25] mm³) (P < 0.05). Conclusion Mild hypothermia can improve the neurological function and reduce the CAM expression and brain edema in the brain tissue of rats with traumatic brain injury, which may be related to the neuroprotective effect of mild hypothermia.

Objective Few studies are reported on the protective effect of valproic acid (VPA) against traumatic brain injury (TBI) by down-regulating the protein expressions of matrix metalloproteinase-9 (MMP-9) and aquaporin-4 (AQP-4) in the brain tissue. This study aimed to investigate the neuroprotective effects of different doses of VPA against TBI in experimental rats. Methods We randomly divided 100 adult male rats into five groups of equal number, sham operation, TBI model, and low- (30 mg), medium- (150 mg) and high-dose (300 mg) VPA treatment. At 1, 3, 7 and 14 days after modeling by controlled cortex impact, we obtained the modified Neurological Severity Scores (mNSS), measured the VPA concentration in the venous blood, and then killed the rats and harvested the brain tissue for determination of the water content using the dry-wet method and the expressions of MMP-9 and AQP-4 by Western blot and immunohistochemistry. Results At 1, 3, 7 and 14 days after modeling, the mNSSs in the high-dose VPA group were 4.6 ± 1.3, 3.8 ± 1.3, 3.0 ± 0.7 and 1.8 ± 0.8, respectively, significantly lower than 8.4 ± 0.9, 7.0 ± 0.7, 5.8 ± 1.0 and 4.5 ± 1.3 in the TBI group (P < 0.05), decreasing in a time-dependent manner, with statistically significant difference between any two dose groups (P < 0.05). At 1, 3 and 7 days, the water contents in the brain tissue were (76.2 ± 0.7)%, (76.9 ± 1.7)% and (73.9 ± 1.3)% in the high-dose VPA group, significantly lower than (79.6 ± 0.8)%, (82.6 ± 0.8)% and (78.6 ± 0.7)% in the TBI group (P < 0.05), also decreasing in a time-dependent manner, with statistically significant difference between any two dose groups (P < 0.05). At 1 and 3 days, the expressions of MMP-9 and AQP-4 in the brain tissue were markedly down-regulated in the VPA groups in a dose-dependent manner as compared with those in the TBI group (P < 0.05), with statistically significant difference between any two dose groups (P < 0.05), and meanwhile immunohistochemistry showed large numbers of cells with positive expressions of MMP-9 and AQP-4, which were reduced with the increased dose of VPA. Conclusion VPA has a neuroprotective effect against TBI in rats by inhibiting the expressions of MMP-9 and AQP-4 proteins in the brain tissue and alleviating brain edema. Within the range of the doses studied, higher-dose VPA produces a better effect.

N6-methyladenosine(m6A), the most common, abundant, and conserved RNA modification in eukaryotic cells, regulates RNA splicing, stability, output, degradation and translation through m6A methyltransferase, m6A demethylase, and m6A methylated binding proteins. Recent studies have found that abnormal m6A methylation may mediate a variety of pathological processes in eyes and participate in the occurrence and development of metabolic, inflammatory, degenerative ocular diseases and ocular tumors, such as diabetic retinopathy, cataract, age-related macular degeneration and uveal melanoma. This review aims to summarize the roles of m6A methylation modification in ocular cells and ocular diseases, elucidate the potential molecular mechanisms of m6A methylation in ocular diseases, so as to encourage innovative approaches in the treatment of these ocular diseases.

Alzheimer's disease(AD)is a common degenerative disease of the central nervous system in which neuropathological changes precede cognitive dysfunction and behavioral impairment. Currently, early diagnosis of AD is based on invasive and expensive testing techniques that are difficult to use widely in the clinical setting. Therefore, there is an urgent need for new markers to detect AD at an early stage. The eye, as an extension of the brain, has been found to show earlier onset of ocular pathologic changes in patients with AD compared to brain pathologic changes, such as retinal structural abnormalities, visual dysfunction, retinal abnormal protein accumulation, choroidal thickness changes, decreased corneal nerve fiber density, deposition of abnormal Aβ proteins in the lens, and pupillary light decreased sensitivity of response, etc. This article reviews the ocular pathologic changes in AD patients in recent years to provide new ideas for the early clinical diagnosis of AD.