ABSTRACT
Background It has been found that fluoride may cause cell damage by inducing intracellular calcium overload. Store-operated calcium entry (SOCE) plays an important role in maintaining intracellular calcium homeostasis, but the effect of fluoride on renal SOCE is unknown. Objective To explore the renal toxicity and the expression levels of the key proteins of SOCE, stromal interaction molecule 1 (STIM1) and calcium release-activated calcium modulator 1 (ORAI1) in the kidney tissues of mice exposed to fluoride subchronically. Methods Twenty male ICR mice were randomly divided into four groups with five mice in each group, including 0 (control group), 0.3, 3, and 30 mg·L−1 fluoride groups. The mice were given drinking water containing designed fluoride for 12 weeks. Body weight and liver and kidney organ coefficients of the mice were measured after the exposure; histopathological changes of the mouse kidney were observed; 24 h urine was collected at the end of 12 weeks of exposure to determine the levels of urine creatinine (UCr), urine calcium (UCa), albumin (ALB), and β2-microglobulin (β2-MG); the protein expression levels of STIM1 and ORAI1 in the kidney were detected by Western blotting; the fluorescence co-localization of STIM1 and ORAI1 was used to further verify the expression levels of STIM1 and ORAI1. Results After the exposure, there were no differences in body weight as well as liver and kidney organ coefficients among the groups (P > 0.05). Under optical microscope, the renal tubular cell showed degeneration, apical protrusion, shedding, and dilation in the 3 and 30 mg·L−1 fluoride groups. There was no statistical difference in UCr among the mice in each group (P > 0.05). Compared with the control group, the levels of UCa adjusted by UCr in the 3 and 30 mg·L−1 fluoride groups were (0.075±0.014) and (0.081±0.012) mol·mol−1 (represent by UCr per mol), which had a rising trend but showed no statistical difference. No difference was identified in the level of ALB among the groups (P > 0.05). The levels of β2-MG showed difference in different exposure groups, and the level of urine β2-MG in the 30 mg·L−1 fluoride group was (0.077±0.014) g·mol−1, higher than that in the control group (P<0.05). Based on the results of Western blotting, the protein expression levels of STIM1 and ORAI1 showed significant differences among the groups (F=18.411, 6.853; P=0.001, 0.013); compared with the control group, the expression levels of STIM1 protein increased in the 3 and 30 mg·L−1 fluoride groups (P < 0.05), and the protein expression level of ORAI1 in the 30 mg·L−1 fluoride group was increased (P < 0.05). The fluorescence co-localization results of STIM1 and ORAI1 showed that the expressions of STIM1 and ORAI1 were up-regulated in the 3 and 30 mg·L−1 fluoride groups. Conclusion Subchronic exposure to fluoride through drinking water can up-regulate the expression levels of STIM1 and ORAI1 in renal tissues and induce renal injury.
ABSTRACT
Objective @#To study the damage effect of sunlight ultraviolet exposure on skin.@*Methods @#No exposure group, low exposure group and high exposure group were set up with 10 mice in each. The exposure doses of sunlight ultraviolet were 0, 10 J/cm2 and 20 J/cm2, respectively. The skin of mice was irradiated by a sunlight ultraviolet simulator for 5 days a week, 13 weeks. At the end of the experiment, the skin appearance of mice was examined; the skin moisture, oil content, texture density, hydroxyproline ( HYP ), hyaluronic acid (HA), malondialdehyde ( MDA ), glutathione ( GSH ) and superoxide dismutase ( SOD ) activities were detected; and the skin tissue morphology, collagen fiber morphology and elastic fiber morphology were observed. @*Results @#The skin appearance of mice in the no exposure group was normal; in the low exposure group, only one mouse had mild skin desquamation; in the high exposure group, the skin was loose and wrinkled, dry and desquamated, local thickening and erythema formation. Compared with the no exposure group, the contents of skin moisture, HYP, HA and SOD activity were lower, texture density, MDA content, morphological scores of skin tissue, collagen fiber tissue and elastic fiber tissue were higher in the high exposure group ( all P<0.05 ). Compared with the low exposure group, the HA content and SOD activity were lower, the skin texture density, MDA content, and histomorphological scores of skin tissue and collagen fibers were higher in the high exposure group ( all P<0.05 ).@*Conclusion @#Exposure to 20 J/cm2 sunlight ultraviolet can significantly lead to abnormal skin appearance and function in mice.
ABSTRACT
Background: Mitragyna speciosa (MS) or ketum is primarily found in Southeast Asia, particularly in northern Malaysia and Thailand. The medicinal value of this plant has attracted significant attention from both herbal medicine practitioners and scientists worldwide. Despite having illegal consumption status, the plant merits study. We conducted a series of experiments to test our hypothesis that ketum impairs both learning and memory in rats. Methods: Ketum leaves were extracted using methanol and standardised for the amount of its pure compound, mitragynine. Rats were divided into groups for a passive avoidance task and long-term potentiation (LTP) extracellular recording. In the extracellular recording condition, rats were grouped into control, MS100 (100 mg/kg of ketum extract), MS200 (200 mg/kg of ketum extract), and MS500 (500 mg/kg of ketum extract) groups. An additional group that received morphine was included in the passive avoidance task (10 mg/kg), and there were six animals per group. Rats received daily treatments orally for 28 days for both experiments. Result: Using a passive avoidance task, our data revealed that the rats' memory significantly increased with increasing doses of MS compared to the morphine-treated group. Our findings from LTP recordings showed that LTP was fully blocked by the higher doses of MS. Conclusion: We speculate on the possibility that additional factors were involved in the passive avoidance task because it was an in vivo animal study, while the LTP experiment solely involved brain slices.