Objective To investigate the effect of lipin1(LPIN1)on the progression of Parkinson's disease(PD)in rats and the possible molecular mechanism of its regulation.Methods The PD rat model was established by injection of 6-Hydroxydopamine hydrobromide(6-OHDA)into the medial forebrain tract of rats,and the LPIN1-overexpressing adenovirus was stably transfected to evaluate the behavioral changes of rats.The content of Fe2+and Glutathione(GSH)and the protein level of tyrosine hydroxylase(TH)in rat brain were detected,and HE staining was used to observe the pathological changes in rat brains.The PD cell model was constructed in vitro,and TH,α-synuclein(α-syn),LPIN1 protein levels and cell viability were detected.LPIN1 small interfering siRNA sequence and overexpression vector and peroxisome proliferator-activated receptor(PPARA)small interfering(siRNA)and overexpression vector were transfected,or ferroptosis inducer erastin was used to treat cell for 24 h,then cells were treated with 6-OHDA for 48h.The levels of Fe2+,reactive oxygen species(ROS),malondialdehyde(MDA),GSH and inflammatory factors in cells were detected to evaluate ferroptosis.Cell viability was detected with CCK-8,and the expressions of ferroptosis related proteins were detected with Western blot.The interacting protein PPARA of LPIN1 was predicted by STRING database and verified by Co-IP analysis.The binding site of PPARA to the promoter of solute carrier family 47 member 1(SLC47A1)was predicted by JASPAR bioinformatics and verified by Ch-IP analysis.Results The fur of the rats in the model group was frightened,and PD symptoms such as continuous tremor,slow movement and weakened activity were shown.The motor behavior and PD symptoms of LPIN1 group were improved/alleviated compared with the model group.Compared with the sham operation group,the total distance of the model group was shortened,the average speed was reduced,and the step length was reduced,while the total resting time was prolonged,the step width was widened,and the gait variation rate was increased,and the differences were significant(t=4.470～26.556,all P＜0.05).Compared with sham operation group,Fe2+content in brain tissue of model group was increased,while GSH content and TH protein expression were decreased,with significance differences(t=8.305,13.305,7.709,all P＜0.05).Compared with the model group,the behavioral evaluation,the level of indexes and the pathological changes of brain tissue in LPIN1 group were improved/alleviated.In addition,6-OHDA decreased PC-12 cell viability,reduced the levels of TH and LPIN1 protein,and increased the level of α-syn protein in a dose-dependent manner,and the differences were significant(F=31.023,7.350,9.124,15.841,all P＜0.05).Silencing LPIN1 intensified the inhibitory effect of 6-OHDA on the viability of PC-12 cells(t=2.209,P＜0.05),and overexpression of LPIN1 could counteract the effect of 6-OHDA.Overexpression of Lpin1 decreased the secretion of IL-1β and IL-6,increased the protein levels of SLC47A1 and GPX4,decreased the levels of Fe2+,MDA and ROS,and increased GSH content(t=3.013～11.639,all P＜0.05).Erastin reversed the inhibitory effect of Lpin1 overexpression on ferroptosis,and reduced the viability of PC-12 cells(t=3.087～7.581,all P＜0.05).LPIN1 interacted with PPARA protein and promoted PPARA expression,while PPARA bound to SLC47A1 promoter and promoted SLC47A1 transcriptional activation.Overexpression of PPARA counteracted the effect of Lpin1 silencing on PC-12 cells.Conclusion Overexpression of LPIN1 may reduce neuronal cell apoptosis by inhibiting ferroptosis mediated by PPARA/SLC47A1 axis,thus alleviating the progression of PD model rats.

Objective To assess inter-observer variations(IOV)in the delineation of target volumes and organs-at-risk(OAR)for intensity-modulated radiotherapy(IMRT)of nasopharyngeal carcinoma(NPC)among physicians from different levels of cancer centers,thereby providing a reference for quality control in multi-center clinical trials.Methods Twelve patients with NPC of different TMN stages were randomly selected.Three physicians from the same municipal cancer center manually delineated the target volume(GTVnx)and OAR for each patient.The manually modified and confirmed target volume(GTVnx)and OAR delineation structures by radiotherapy experts from the regional cancer center were used as the standard delineation.The absolute volume difference ratio(△V_diff),maximum/minimum volume ratio(MMR),coefficient of variation(CV),and Dice similarity coefficient(DSC)were used to compare the differences in organ delineation among physicians from different levels of cancer centers and among the 3 physicians from the same municipal cancer center.Furthermore,the IOV of GTVnx and OAR among physicians from different levels cancer centers were compared across different TMN stages.Results Significant differences in the delineation of GTVnx were observed among physicians from different levels of cancer centers.Among the 3 physicians,the maximum values of △V_diff,MMR,and CV were 97.23%±83.45%,2.19±0.75,and 0.31±0.14,respectively,with an average DSC of less than 0.7.Additionally,there were considerable differences in the delineation of small-volume OAR such as the left and right optic nerves,chiasm,and pituitary,with average MMR>2.8,CV>0.37,and DSC<0.51.However,relatively smaller differences were observed in the delineation of large-volume OAR such as the brainstem,spinal cord,left and right eyeballs,and left and right mandible,with average△V_diff<42%,MMR<1.55,and DSC>0.7.Compared with the differences among physicians from different levels cancer centers,the differences among the 3 physicians from the municipal cancer center were slightly reduced.Furthermore,there were also differences in the delineation of target volumes for NPC among physicians from different levels cancer centers,depending on the staging of the disease.Compared with the delineation of target volumes for earlier stage patients(stages I or II),the differences among physicians in the delineation of target volumes for advanced stage patients(stages III or IV)were smaller,with average △V_diff and DSC of 98.31%±67.36%vs 69.38%±72.61%(P<0.05)and 0.55±0.08 vs 0.72±0.12(P<0.05),respectively.Conclusion There are differences in the delineation of GTVnx and OAR in radiation therapy for NPC among physicians from different levels of cancer centers,especially in the delineation of target volume(GTVnx)and small-volume OAR for early-stage patients.To ensure the accuracy of multicenter clinical trials,it is recommended to provide unified training to physicians from different levels of cancer centers and review their delineation results to reduce the effect of differences on treatment outcomes.