Injectable biomimetic hydrogels are a promising strategy for enhancing tissue repair after spinal cord injury (SCI) by restoring electrical signals and increasing stem cell differentiation. However, fabricating hydrogels that simultaneously exhibit high electrical conductivities, excellent mechanical properties, and biocompatibility remains a great challenge. In the present study, a collagen-based self-assembling cross-linking polymer network (SCPN) hydrogel containing poly-pyrrole (PPy), which imparted electroconductive properties, is developed for potential application in SCI repair. The prepared collagen/polypyrrole (Col/PPy)-based hydrogel exhibited a continuous and porous structure with pore sizes ranging from 50 to 200 μm. Mechanical test results indicated that the Young’s moduli of the prepared hydrogels were remarkably enhanced with PPy content in the range 0–40 mM. The conductivity of Col/PPy40 hydrogel was 0.176 ± 0.07 S/cm, which was beneficial for mediating electrical signals between tissues and accelerating the rate of nerve repair. The investigations of swelling and degradation of the hydrogels indicated that PPy chains interpenetrated and entangled with the collagen, thereby tightening the network structure of the hydrogel and improving its stability. The cell count kit-8 (CCK-8) assay and live/dead staining assay demonstrated that Col/PPy40 coupled with electrical simulation promoted the proliferation and survival of neural stem cells (NSCs). Compared with the other groups, the immunocytochemical analysis, qPCR, and Western blot studies suggested that Col/PPy40 coupled with ES maximally induced the differentiation of NSCs into neurons and inhibited the differentiation of NSCs into astrocytes. The results also indicated that the neurons in ES-treated Col/PPy40 hydrogel have longer neurites (170.8 ± 37.2 μm) and greater numbers of branch points (4.7 ± 1.2). Therefore, the prepared hydrogel system coupled with ES has potential prospects in the field of SCI treatment.

It is worth noting that neuroinflammation is well recognized as a symptom of neurodegenerative diseases (NDs). The regulation of neuroinflammation becomes an attractive focus for innovative ND treatment technologies. There is evidence that IL-22 is associated with the development and progression of a wide assortment of NDs. For example, IL-22 can activate glial cells, causing them to generate pro-inflammatory cytokines and encourage lymphocyte infiltration in the brain. IL-22 mRNA is highly expressed in Alzheimer’s disease (AD) patients, and a high expression of IL-22 has also been detected in the brains of patients with other NDs. We examine the role of IL-22 in the development and treatment of NDs in this review, and we believe that IL-22 has therapeutic potential in these diseases.

Background: Plate fixation using traditional lateral L-shape approach for intra-articular calcaneal fractures is complicated by 30% of wound complications, and the lateral small incision techniques with a tarsal sinus approach cannot sufficiently address all the fragments. A modified tarsal sinus approach with combined advantages of traditional lateral L-shape and tarsal sinus approaches for the treatment of intra-articular calcaneal fractures was developed. Method: This prospective study included 29 patients (13 Sanders type II and 16 type III) with calcaneal fractures were managed with this technique. Calcaneal height, width, length, Bohler's angle, and Gissane angle were measured preoperatively, postoperatively, and at 1-year follow-up. Functional outcomes were assessed based on American Orthopedic Foot and Ankle Society (AOFAS) ankle/hindfoot score. Results: Twenty-nine patients with average follow-up time of 18 (range 13-29) months were included. The radiographs demonstrated significant corrections of the Bohler's angle and Gissane angle, calcaneal width, length, and height from preoperation to postoperation and 1-year follow-up. Among all follow-up patients, one case had skin necrosis but healed after dressing. Another case had symptoms of numbness in the sural innervation area, which disappeared after 5 months of physical therapy and drug therapy. One case showed degenerative changes of subtalar joint at 1-year follow-up. No other wound complications like incision infection (superficial or deep) and wound dehiscence occurred. At 1-year follow-up, the mean AOFAS score was 90.2 + 17.7 (range 70-98) and the good and excellent rate was 89.7%. Conclusion: The modified tarsal sinus approach in the treatment of Sander's type II and III calcaneal fractures allowed adequate reduction and rigid fixation with low incidence of wound complications. Compared to sinus tarsi approach, this technique required shorter learning curve and was more easily mastered by young orthopedic surgeons. Thus, it was worthy of application clinically.