ABSTRACT
Objective:To investigate the expression and significance of endoplasmic reticulum stress apoptosis pathway related proteins in renal cortex of rats with chronic fluorosis.Methods:Twenty four healthy SD rats were divided into 4 groups (6 rats/group, half male and half female) according to their body mass (100 - 120 g) by random number table method, rats in control group drank tap water (fluoride content < 0.5 mg/L), and in low, medium and high fluoride groups drank tap water with fluoride content (sodium fluoride) of 10, 50 and 100 mg/L, respectively. After 180 days of feeding, dental fluorosis was examined, 24-hour urine sample was collected and the content of fluoride in urine was detected by fluoride ion selective electrode method. Renal tissue was taken after anesthesia, and the pathological changes of renal cortex were observed by hematoxylin-eosin (HE) staining. The expressions of endoplasmic reticulum stress apoptosis pathway related proteins [inositol-requiring enzyme 1α (IRE1α), apoptosis signal-regulating kinase 1 (ASK1), C-Jun N-terminal kinase (JNK) and phosphorylated JNK (P-JNK)] were determined by immunohistochemical staining in rat renal cortex.Results:No dental fluorosis was found in control group. The incidence of dental fluorosis in low, medium and high fluoride groups were 2/6, 5/6 and 6/6, respectively. Compared with control group [(5.707 ± 1.190) mg/L], the urinary fluoride in low, medium and high fluoride groups [(17.028 ± 3.006), (34.378 ± 12.045), (94.759 ± 31.773) mg/L] was significantly higher ( P < 0.05), and the urinary fluoride in high fluoride group was higher than that in low and medium fluoride groups ( P < 0.05). HE staining showed that, compared with control group, the cell volume of renal tubules and glomeruli in medium and high fluoride groups increased, the cells arranged closely, and the eosinophilia of the cytoplasm increased. The immunohistochemical staining results showed that there was no significant difference in the expression of JNK protein in rat renal cortex between control group and low, medium and high fluoride groups ( F = 0.07, P > 0.05). The expressions of IRE1α, ASK1 and P-JNK proteins in rat renal cortex in high fluoride group were higher than those of control, low and medium fluoride groups ( P < 0.05), and the expressions of IRE1α and ASK1 proteins in medium fluoride group were significantly higher than those in control and low fluoride groups ( P < 0.05). Conclusion:Long-term excessive fluoride intake can lead to renal cortex injury in rats, and the mechanism of injury may be related to the activation of IRE1α-ASK1-JNK endoplasmic reticulum stress apoptosis pathway.
ABSTRACT
OBJECTIVE：To investigate the improvement e ffects of Zingiber officinale decoction （ZOD） on doxorubicin （DOX）-induced mitochondrial function injury of H 9c2 cardiomyocytes. METHODS ：Taking H 9c2 cardiomyocytes as research object，the effects of different concentrations of ZOD （0.125，0.25，0.5，1，2，4，8 mg/mL，by crude drug ，the same below ）on its survival rate were investigated by CCK- 8 assay. The effects of low ，medium and high concentrations of ZOD （0.125，0.25，0.5 mg/mL）on the morphology of H 9c2 cardiomyocytes after DOX （5 μmol/L）induced mitochondrial dysfunction were detected by high content living cell imaging system. The relative number of cells ，the relative fluorescence intensity of living cells and the relative fluorescence intensity of dead cells were analyzed quantitatively. The effects of ZOD （0.5 mg/mL）on related indexes of mitochondrial respiratory function （oxygen consumption rate ，extracellular acidification rate ，baseline oxygen consumption rate ， baseline extracellular acidification rate ，stress oxygen consumption rate and stress extracellular acidification rate ） and energy metabolism（basic respiration level ，maximum respiration level ，ATP production level ，H+ proton leakage level ，spare respiration level and non-mitochondrial respiration level ）were detected by bioenergy analyzer. RESULTS ：After treated with 0.125，0.25，0.5 mg/mL ZOD ，the survival rate of H 9c2 cardiomyocytes were increased significantly （P＜0.01）or had no statistical significance （P＞0.05）. After DOX induced mitochondrial dysfunction of H 9c2 cardiomyocytes，pretreated with 0.125，0.25，0.5 mg/mL（or 0.5 mg/mL）ZOD，the morphology of H 9c2 cardiomyocytes returned to normal and showed regular fibrous adherent distribution. The relative cell number ，fluorescence intensity of living cells ，oxygen consumption rate ，extracellular acidification rate ，baseline oxygen consumption rate ，baseline extracellular acidification rate ，stress oxygen consumption rate ，stress extracellular acidification rate，basic respiration level ，maximal respiration level ，ATP production level ，spare respiration level and non-mitochondrial respiration level were all significantly increased （P＜0.05 or P＜0.01），while relative dead cell fluorescence intensity and H + proton leakage level were significantly decreased （P＜0.01）. CONCLUSIONS ： ZOD can improve the respiratory function and mitochondrial energy metabolism of H 9c2 cardiomyocytes，so as to improve mitochon drial function injury.
ABSTRACT
Objective:To observe the changes of phosphorylated N-methyl-D-aspartate receptor (P-NMDAR) subunit and calmodulin-dependent protein kinase Ⅱ (CaMK Ⅱ) protein expression in the brain tissue of rats with chronic fluorosis, and to explore the molecular pathogenesis of chronic fluorosis nerve injury.Methods:Eighteen one-month-old SD rats (half male and half female), weighing (100 ± 20) g, were randomly divided into three groups after adaptive feeding for 1 week: control group (drinking tap water, fluoride content < 0.5 mg/L), low fluoride group (drinking water fluoride content was 10.0 mg/L) and high fluoride group (drinking water fluoride content was 100.0 mg/L), with 6 rats in each group (half male and half female). Brain tissue was harvested after 180 days of feeding. HE staining was used to observe the morphological changes of rat brain tissue, Nissl staining was used to observe the changes of Nissl bodies in nerve cells, and immunohistochemical staining was used to observe the expressions of P-NMDAR subunits (P-NMDAR1, P-NMDAR2A) and CaMK Ⅱ protein in rat brain tissue.Results:Under light microscope, HE staining showed disordered arrangement of hippocampal neurons, nuclear hyperstaining and basophilic enhancement in the high fluoride group. The results of Nissl staining showed that the average optical density of Nissl bodies in nerve cells in the hippocampus of rats in the control group, low fluoride group, and high fluoride group were 0.024 4 ± 0.009 7, 0.024 0 ± 0.003 1, and 0.023 9 ± 0.013 8, respectively. There was no statistically significant difference between the groups ( F = 0.010, P > 0.05). Compared with the control group (0.011 8 ± 0.006 5, 0.065 6 ± 0.011 1, 0.143 8 ± 0.029 9) and low fluoride group (0.017 2 ± 0.006 8, 0.062 6 ± 0.017 8, 0.135 6 ± 0.029 6), the protein expressions of P-NMDAR1, P-NMDAR2A and CaMK Ⅱ in high fluoride group were significantly increased (0.026 3 ± 0.005 7, 0.086 3 ± 0.009 0, 0.210 9 ± 0.048 7, P < 0.05); and the protein expression of P-NMDAR1 in low fluoride group was higher than that in the control group ( P < 0.05). Conclusion:Long-term excessive fluoride intake can lead to nerve cell injury in rats, and the mechanism of injury maybe related to the excitotoxicity induced by calcium ion (Ca 2+) overload caused by overactivation of NMDAR subunits.
ABSTRACT
Objective:To observe the change of growth and development, learning and memory, and oxidative stress in serum of offspring rats with fluorosis, and to explore the mechanism of fluoride on neurobehavioral development of offspring rats.Methods:Seventy-two SD rats (female and male ratio 3 ∶ 1) were fed adaptively for one week. According to their body mass [(80 ± 20) g], they were divided into control group (drinking tap water, containing less than 0.5 mg/L fluoride), low fluorine group (drinking water containing 10.0 mg/L of fluoride), and high fluorine group (drinking water containing 100.0 mg/L of fluoride) with random number table. After six months of feeding, they mated freely and gave birth in each group (24 rats with 18 females and 6 males). The rats in each group continued to be exposed to fluoride after giving birth, and the offspring rats were exposed to fluoride through breast milk feeding until the 28th day after birth. Body and brain weight, growth and development indicators (auricle separation, eyes opening, teeth eruption and hair growth) and neurobehavioral development indicators (cliff avoidance, auditory startle, surface righting and vibrissa positioning) were recorded. On the 28th day after birth, the learning and memory abilities (escape latency) of offspring rats were tested by Morris water maze; blood samples were taken from eyeballs to detect the content of nitric oxide (NO), the activity of nitric oxide synthase (NOS) and inducible nitric oxide synthase (iNOS).Results:On the 21st day and 28th day after birth, the differences of body weight among control group, low fluorine group and high fluorine group [21st day: (54.70 ± 3.02), (52.30 ± 2.58), (51.30 ± 2.71) g, 28th day: (91.70 ± 5.03), (90.40 ± 4.76), (86.00 ± 4.55) g] were statistically significant ( F = 3.96, 3.70, P < 0.05); on the 21st day, the body weight of high fluorine group was lower than that of control group ( P < 0.05); on the 28th day, the body weight of the high fluorine group was lower than those of control group and low fluorine group ( P < 0.05). On the 28th day, the difference of brain weight of control group, low fluorine group and high fluorine group was statistically significant ( F = 6.19, P < 0.05); and the low fluorine group and high fluorine group were lower than that of control group ( P < 0.05). Among the growth development indicators, the difference of time of completing eyes opening in control group, low fluorine group and high fluorine group was statistically significant ( F = 3.64, P < 0.05); and the high fluorine group was higher than that of control group ( P < 0.05). In neurobehavioral development indicators, the differences of time of completing cliff avoidance, surface righting between the control group, low fluorine group and high fluorine group were statistically significant ( F = 8.29, 7.69, P < 0.05); and the time of completing cliff avoidance in high fluorine group was higher than those of control group and low fluorine group ( P < 0.05), the time of completing surface righting was higher than that of control group ( P < 0.05). In Morris water maze, on the 4th day, the escape latencies of low fluorine group and high fluorine group were higher than that of control group ( P < 0.05). The results of oxidative stress in serum showed that there were statistically significant differences in serum NO content, NOS and iNOS activitives between the control group, low fluorine group and high fluorine group ( F = 4.86, 66.48, 70.95, P < 0.05); and the NO content of the high fluoirne group was higher than that of the control group ( P < 0.05), the activities of NOS and iNOS of the high fluoirne group were higher than those of control group and the low fluorine group ( P < 0.05). Conclusion:Excessive fluoride can increase the level of oxidative stress in serum, which may be closely related to the neurobehavioral retardation and the decline of learning and memory ability of offspring rats.