Mitochondria not only serve as the central hub for cellular energy metabolism,but also participate in crucial physiological processes such as signal transduction and activity regulation.Abnormal mitochondrial quantity,imbalance in mtDNA copy number,accumulation of genetic mutations,and aberrant activation of autophagic pathways can lead to mitochondrial dysfunction or even organelle disorders,while activating mechanisms of cellular damage and death,consequently contributing to the pathogenesis of various diseases.As a highly selective form of autophagy,mitophagy plays a pivotal regulatory role in organelle quality control and homeostasis maintenance.This article focuses on the classic PINK1/Parkin pathway-mediated mitophagy as an entry point,summarizing recent research advances regarding the role of mitophagy in neurodegenerative diseases,aiming to provide novel insights for developing targeted mitophagy regulation strategies to improve prevention and treatment approaches for neurodegenerative disorders.

Objective:To investigate the role and mechanism of human umbilical cord mesenchymal stem cell exosomes (hUCMSC-ex) in wounds with escharectomy and skin grafting in scalded rats.Methods:The study was an experimental study. Twelve male Sprague-Dawley (SD) rats aged 6-8 weeks were divided into combined treatment group, fixed+allogeneic skin group, autologous skin+allogeneic skin group, and allogeneic skin group by random number table method (the same grouping method hereinafter), with 3 rats in each group. The four groups of rats were inflicted with scalded wounds on the back and performed with escharectomy, and then the wounds of rats in combined treatment group were fixed with a metal ring (the same fixing method hereinafter) and transplanted with autologous skin grafts and allogeneic skin grafts, and the other three groups of rats were fixed and/or transplanted with skin grafts corresponding to the group name. At 14, 21, and 28 d after surgery, the wound healing area in the four groups of rats was measured. Another 15 male SD rats aged 6-8 weeks were divided into normal group with no treatment, high exosome group, low exosome group, supernatant group, and phosphate buffer solution (PBS) group, with 3 rats in each group. The last 4 groups of rats were treated as that in the above-mentioned combined treatment group, and then were injected around the wounds with 200 μL of PBS containing 100 μg of hUCMSC-ex, 200 μL of PBS containing 50 μg of hUCMSC-ex, 200 μL of supernatant with no hUCMSC-ex, and 200 μL of PBS at 0 (immediately), 7, 14, and 21 d after surgery, respectively. At 14, 21, and 28 d after surgery, the wound healing area in the four groups of rats was measured. The wound neo-epithelial tissue of rats in high exosome group and PBS group at 28 d after surgery and the normal skin tissue of rats in normal group at the same time point were taken, and the differentially expressed proteins were screened by label-free quantitative proteomics method; the two up-regulated and differentially expressed proteins, the immunoglobulin G1 heavy chain constant region (IGHG1) and cystatin A (CSTA) with the largest and second largest fold changes in comparison between high exosome group and PBS group were selected, and their protein expressions were detected by Western blotting. The number of samples in all experiments was 3.Results:At 14, 21, and 28 d after surgery, the wound healing area in combined treatment group, autologous skin+allogeneic skin group, and allogeneic skin group of rats was significantly larger than that in fixed+allogeneic skin group ( P<0.05), the wound healing area in autologous skin+allogeneic skin group of rats at 21 d after surgery and that in allogeneic skin group of rats at 14 and 21 d after surgery was significantly larger than that in combined treatment group ( P<0.05), and the wound healing area in allogeneic skin group of rats at 14 d after surgery was significantly larger than that in autologous skin+allogeneic skin group ( P<0.05). The wound healing area of rats in high exosome group and low exosome group at 14, 21, and 28 d after surgery and in supernatant group at 14 and 28 d after surgery was significantly larger than that in PBS group ( P<0.05); the wound healing area in high exosome group of rats at 14 and 21 d after surgery was significantly larger than that in supernatant group ( P<0.05), and the wound healing area at 14 d after surgery was significantly larger than that in low exosome group ( P<0.05); the wound healing area in low exosome group of rats at 14 d after surgery was significantly larger than that in supernatant group ( P<0.05). Compared with that in PBS group, 332 proteins were differentially expressed in the neo-epithelial tissue of the wounds in high exosome group of rats at 28 d after surgery ( P<0.05), among which the protein expressions of IGHG1 and CSTA were significantly up-regulated (with fold change of 12.60 and 2.27, respectively, P<0.05). Compared with those of normal skin tissue in normal group, 1 400 and 1 057 proteins were differentially expressed in the neo-epithelial tissue of the wounds in high exosome group and PBS group of rats at 28 d after surgery, respectively. The protein expressions of IGHG1 and CSTA in the wound neo-epithelial tissue in high exosome group of rats at 28 d after surgery were significantly larger than those in normal skin tissue of rats in normal group ( P<0.05) and those in PBS group ( P<0.05). Conclusions:hUCMSC-ex may accelerate the repair process of wounds with escharectomy and skin grafting and improve the quality of wound healing in scalded rats by regulating the protein expressions of IGHG1 and CSTA.

Objective:To investigate the effect of Salvia miltiorrhiza injection combined with human adipose derived stem cells (hADSC) on the survival rate of autologous fat granules implanted in nude mice.Methods:A total of 24 healthy 8 weeks old female nude mice weighing (23±3) g were randomly divided into four groups ( n=6): Group A was given fat granules 0.5 ml; Group B: fat granules 0.5 ml+ hADSC; Group C: Salvia miltiorrhiza 0.5 g/(kg·d) + fat granules 0.5 ml, and Group D: Salvia miltiorrhiza injection 0.5 g/(kg·d) + fat granules + enrichment. 3 nude mice were randomly selected from each group for 15 days after transplantation and stained with conventional HE. Immunohistochemical staining was performed to count the number of microvessels. On the 30th day after surgery, the remaining 3 nude mice in each group were sacrificed. The specimens were stained with HE and the volume of each specimen was measured. Results:Graft appearance was observed by naked eye: 15 days after the operation, all the specimens were formed completely. The new capillaries were shaped on the surface of the capsule. The boundaries of the capsule and the surrounding tissue were obvious. The activity was good, the hardness of the texture was medium, and the loose connective tissue was connected to the surrounding tissue. On the 30 day after operation, the volume of the graft was smaller than that at the beginning of transplantation, and fat liquefaction and necrosis were seen in some tissues. Blood vessel density values of immunohistochemical sections of fat transplantation in each group 15 days after surgery were compared pairwisely. The differences between the groups were statistically significant ( P<0.05). Lsd-t method was used for pairwise comparison of fat graft volume values of each group 30 days after surgery, and the difference between each group was statistically significant ( P<0.05). Conclusions:The combined use of Salvia miltiorrhiza injection and hADSCs can effectively promote the reconstruction of the early vascular system of the fat granule transplantation and improve the survival rate of fat particles more effectively than the individual use.