BACKGROUND:Recent studies have found that Nrf2/ARE signaling pathway activators have the characteristics of low toxicity and control,and have a protective effect against radiation tissue damage.OBJECTIVE:To investigate whether nitrooleic acid can protect submandibular gland epithelial cells from radiation injury by regulating the Nrf2/ARE signaling pathway.METHODS:Rat submandibular gland epithelial cells were cultured in vitro and CCK-8 assay was used to screen the optimal concentration and time of nitrooleic acid administration.Submandibular gland epithelial cells were divided into non-radiation group,radiation control group,nitrooleic acid group,nitrooleic acid+ML385(Nrf2/ARE signaling pathway specific inhibitor)group,and ML385 group.Submandibular gland cells were pretreated with nitrooleic acid and ML385 for 24 hous according to the experimental groups,and then irradiated with 5 Gy radiation to establish the models.At 48 hours after irradiation,CCK-8 assay was used to detect the cell proliferation rate.Real-time quantitative PCR was used to detect the expression of Nrf2,HO-1,and NQO1 mRNA in the cells.Real-time quantitative PCR and enzyme-linked immunosorbent assay were used to detect the cell secretion function and the expression of inflammatory factors.DCFH-DA fluorescent probe kit was used to detect the level of intracellular reactive oxygen species.RESULTS AND CONCLUSION:(1)Compared with the radiation control group,the proliferation rate of submandibular gland epithelial cells and the expression levels of secretion function related factors aquaporin 5 and α-amylase in the nitrooleic acid group of rats increased(P＜0.05),and the expression levels of Nrf2,HO-1,and NQO1 mRNA increased(P＜0.05),while the expression levels of inflammatory factors interleukin-1β,interleukin-6,and tumor necrosis factor-αdecreased(P＜0.05),and reactive oxygen species generation reduced(P＜0.01).(2)Compared with the nitrooleic acid group,the addition of nitrooleic acid and ML385 group resulted in a decrease in cell proliferation rate and expression levels of secretion function related factors aquaporin 5 and α-amylase(P＜0.05),and mRNA expressions of Nrf2,HO-1,and NQO1 were all decreased(P＜0.05),while the expression levels of inflammatory factors interleukin-1β,interleukin-6,and tumor necrosis factor-α increased(P＜0.05),and generation of reactive oxygen species increased(P＜0.05).(3)Results indicated that in the radiation environment,nitrooleic acid has a certain protective effect on the proliferation ability and secretion function of rat submandibular gland epithelial cells,reduces the expression of inflammatory factors,lowers intracellular reactive oxygen species levels,and alleviates the damage of rat submandibular gland epithelial cells caused by radiation.This function may be related to the activation of Nrf2/ARE signaling pathway.

BACKGROUND:Recent studies have found that Nrf2/ARE signaling pathway activators have the characteristics of low toxicity and control,and have a protective effect against radiation tissue damage.OBJECTIVE:To investigate whether nitrooleic acid can protect submandibular gland epithelial cells from radiation injury by regulating the Nrf2/ARE signaling pathway.METHODS:Rat submandibular gland epithelial cells were cultured in vitro and CCK-8 assay was used to screen the optimal concentration and time of nitrooleic acid administration.Submandibular gland epithelial cells were divided into non-radiation group,radiation control group,nitrooleic acid group,nitrooleic acid+ML385(Nrf2/ARE signaling pathway specific inhibitor)group,and ML385 group.Submandibular gland cells were pretreated with nitrooleic acid and ML385 for 24 hous according to the experimental groups,and then irradiated with 5 Gy radiation to establish the models.At 48 hours after irradiation,CCK-8 assay was used to detect the cell proliferation rate.Real-time quantitative PCR was used to detect the expression of Nrf2,HO-1,and NQO1 mRNA in the cells.Real-time quantitative PCR and enzyme-linked immunosorbent assay were used to detect the cell secretion function and the expression of inflammatory factors.DCFH-DA fluorescent probe kit was used to detect the level of intracellular reactive oxygen species.RESULTS AND CONCLUSION:(1)Compared with the radiation control group,the proliferation rate of submandibular gland epithelial cells and the expression levels of secretion function related factors aquaporin 5 and α-amylase in the nitrooleic acid group of rats increased(P＜0.05),and the expression levels of Nrf2,HO-1,and NQO1 mRNA increased(P＜0.05),while the expression levels of inflammatory factors interleukin-1β,interleukin-6,and tumor necrosis factor-αdecreased(P＜0.05),and reactive oxygen species generation reduced(P＜0.01).(2)Compared with the nitrooleic acid group,the addition of nitrooleic acid and ML385 group resulted in a decrease in cell proliferation rate and expression levels of secretion function related factors aquaporin 5 and α-amylase(P＜0.05),and mRNA expressions of Nrf2,HO-1,and NQO1 were all decreased(P＜0.05),while the expression levels of inflammatory factors interleukin-1β,interleukin-6,and tumor necrosis factor-α increased(P＜0.05),and generation of reactive oxygen species increased(P＜0.05).(3)Results indicated that in the radiation environment,nitrooleic acid has a certain protective effect on the proliferation ability and secretion function of rat submandibular gland epithelial cells,reduces the expression of inflammatory factors,lowers intracellular reactive oxygen species levels,and alleviates the damage of rat submandibular gland epithelial cells caused by radiation.This function may be related to the activation of Nrf2/ARE signaling pathway.

Objective To investigate the effect of autophagy response on neurological functions and the role of mitogen-activated protein kinases (MAPKs) signaling pathway in rats after traumatic brain injury (TBI).Methods Fifty-four healthy male SD rats were randomly divided into sham-operated group,TBI group and TBI+autophagy inhibitor 3-methyladenine (3-MA) group (n=18).TBI animal models of the later two groups were established using Feeney's method.Rats in the sham-operated group were only performed bone window opening without knock;rats in the TBI+3-MA group were given intraperitoneal injection of 3-MA(5 mg/kg) 30 min after modeling and rats in the other two groups were given the same volume of normal saline.Three and 7 d after modeling,the protein levels of S100B and neuron specific enolase (NSE) in serum were tested with enzyme linked immunosorbent assay (ELISA);modified neurologic severity scale (mNSS) was used to detect the movement,sense and reflex functions;brain water content was measured with wet-dry weight method.The autophagy related factors (LC3-Ⅱ and Beclin-1) and MAPKs signaling pathway related factors (c-Jun N-terminal kinase [JNK],phosphorylated [p]-JNK,extracellular signal-regulated kinase [ERK]1/2,p-ERK1/2,p38MAPK and p-p38MAPK) protein expressions in TBI cerebral cortex were determined by Western blotting.Results As compared with those in the sham-operated group,the brain edema level,mNSS scores,and S100B and NSE protein levels in the TBI group and TBI+3-MA group were significantly increased (P＜0.05);TBI+3-MA group had significantly lower brain edema level,mNSS scores,and S100B and NSE protein levels than TBI group (P＜0.05).The expression levels of autophagy and MAPKs signaling pathway related factors in the TBI group and TBI+3-MA group were significantly higher as compared with those in the sham-operated group (P＜0.05).As compared with the TBI group,TBI+3-MA group had significantly decreased levels of LC3-Ⅱ,Beclin-1 and activation of JNK and p-p38MAPK signaling pathways (P＜0.05).Conclusion Suppressing autophagy response markedly improves neurological outcomes after TBI,possibly mediated by inhibiting activation of JNK and p38MAPK signaling pathways.