Analysis of the femoral neck from rats in the periestropause treated with oxytocin and submitted to strength training

Role of oxytocin in bone

Oxytocin (OT) is a posterior pituitary hormone that, in addition to its role in regulating childbirth and lactation, also exerts direct regulatory effects on the skeleton through peripheral OT and oxytocin receptor (OTR). Bone marrow mesenchymal stem cells (BMSCs), osteoblasts (OB), osteoclasts (OC), chondrocytes, and adipocytes all express OT and OTR. OT upregulates RUNX2, BMP2, ALP, and OCN, thereby enhancing the activity of BMSCs and promoting their differentiation towards OB rather than adipocytes. OT also directly regulates OPG/RANKL to inhibit adipocyte generation, increase the expression of SOX9 and COMP, and enhance chondrocyte differentiation. OB can secrete OT, exerting influence on the surrounding environment through autocrine and paracrine mechanisms. OT directly increases OC formation through the NκB/MAP kinase signaling pathway, inhibits osteoclast proliferation by triggering cytoplasmic Ca2+ release and nitric oxide synthesis, and has a dual regulatory effect on OCs. Under the stimulation of estrogen, OB synthesizes OT, amplifying the biological effects of estrogen and OT. Mediated by estrogen, the OT/OTR forms a feedforward loop with OB. Apart from estrogen, OT also interacts with arginine vasopressin (AVP), prostaglandins (PGE2), leptin, and adiponectin to regulate bone metabolism. This review summarizes recent research on the regulation of bone metabolism by OT and OTR, aiming to provide insights into their clinical applications and further research.

Unilateral biportal endoscopic discectomy versus microdiscectomy for lumbar disc herniation: a systematic review and meta-analysis

PURPOSE

This study aimed to compare unilateral biportal endoscopic discectomy (UBED) with microdiscectomy (MD) for treating lumbar disk herniation (LDH).

METHODS

A comprehensive literature search was conducted in the Embase, PubMed, Cochrane Library, CNKI, and Web of Science databases from database inception to April 2023 to identify studies comparing UBED and MD for treating LDH. This study evaluated the visual analog scale (VAS) score, Oswestry disability index (ODI), Macnab scores, operation time, estimated blood loss, hospital stay, and complications, estimated blood loss, visual analog scale (VAS) score, Oswestry disability index (ODI), and Macnab scores at various pre- and post-surgery stages. The meta-analysis was performed using RevMan 5.4 software.

RESULTS

The meta-analysis included 9 distinct studies with a total of 1001 patients. The VAS scores for low back pain showed no significant differences between the groups at postoperative 1-3 months (P = 0.09) and final follow-up (P = 0.13); however, the UBED group had lower VAS scores at postoperative 1-3 days (P = 0.02). There were no significant differences in leg pain VAS scores at baseline (P = 0.05), postoperative 1-3 days (P = 0.24), postoperative 1-3 months (P = 0.78), or at the final follow-up (P = 0.43). ODI comparisons revealed no significant differences preoperatively (P = 0.83), at postoperative 1 week (P = 0.47), or postoperative 1-3 months (P = 0.13), and the UBED group demonstrated better ODI at the final follow-up (P = 0.03). The UBED group also exhibited a shorter mean operative time (P = 0.03), significantly shorter hospital stay (P < 0.00001), and less estimated blood loss (P = 0.0002). Complications and modified MacNab scores showed no significant differences between the groups (P = 0.56 and P = 0.05, respectively).

CONCLUSION

The evidence revealed no significant differences in efficacy between UBED and MD for LDH treatment. However, UBED may offer potential benefits such as shorter hospital stays, lower estimated blood loss, and comparable complication rates.

The microarchitecture and chemical composition of the femur neck of senescent female rats after different physical training protocols

A sedentary lifestyle, coupled with a decrease in estrogen, impairs bone homeostasis, favoring to the development of osteopenia and osteoporosis, both recognized as risk factors for fractures. Here, we investigated the quality of the femur, particularly the femur neck region, and the ambulation performance of senescent rats subjected to three different physical training protocols during the periestropause period. Forty-eight female rats, 18 months of age, were subjected to a 120-day training period, three times a week. The rats were distributed into four groups: aerobic training (AT), strength training (ST), concurrent training (CT), or no training (NT). After the experimental period, at 21 months of age, ambulation performance and femur were analyzed using microtomography, Raman stereology, densitometry, and mechanical strength tests. The results demonstrated greater remodeling activity and improvement in resistance and bone microarchitecture in the femur neck of senescent female rats after undergoing physical training. Our verified higher intensities of bands related to collagen, phosphate, amide III, and amide I. Furthermore, the analysis of the secondary collagen structures indicated alterations in the collagen network due to the exercise, resulting in increased bone strength. Both AT and strength-based training proved beneficial, with AT showing greater adaptations in bone density and stiffness in the femur, while strength-based training greater adaptations in trabecular and cortical structure. These insights contribute to the understanding of the potential interventions for preventing osteopenia and osteoporosis, which are critical risk factors for fractures.

The mechanism of oxytocin and its receptors in regulating cells in bone metabolism

Oxytocin (OT) is a neuropeptide known to affect social behavior and cognition. The epigenetic modification of the oxytocin receptor (OTR) via DNA methylation stimulates parturition and breast milk secretion and inhibits craniopharyngioma, breast cancer, and ovarian cancer growth significantly as well as directly regulates bone metabolism in their peripheral form rather than the central form. OT and OTR can be expressed on bone marrow mesenchymal stem cells (BMSCs), osteoblasts (OB), osteoclasts (OC), osteocytes, chondrocytes, and adipocytes. OB can synthesize OT under the stimulation of estrogen as a paracrine-autocrine regulator for bone formation. OT/OTR, estrogen, and OB form a feed-forward loop through estrogen mediation. The osteoclastogenesis inhibitory factor (OPG)/receptor activator of the nuclear factor kappa-B ligand (RANKL) signaling pathway is crucially required for OT and OTR to exert anti-osteoporosis effect. Downregulating the expression of bone resorption markers and upregulating the expression of the bone morphogenetic protein, OT could increase BMSC activity and promote OB differentiation instead of adipocytes. It could also stimulate the mineralization of OB by motivating OTR translocation into the OB nucleus. Moreover, by inducing intracytoplasmic Ca²⁺ release and nitric oxide synthesis, OT could regulate the OPG/RANKL ratio in OB and exert a bidirectional regulatory effect on OC. Furthermore, OT could increase the activity of osteocytes and chondrocytes, which helps increase bone mass and improve bone microstructure. This paper reviews recent studies on the role of OT and OTR in regulating cells in bone metabolism as a reference for their clinical use and research based on their reliable anti-osteoporosis effects.

Design and application of personalized exercise prescription for primary osteoporosis

BACKGROUND

Regular exercise has been shown to have a beneficial effect on primary osteoporosis (POP). However, current exercise prescriptions have limitations such as insufficient individualized features and low participant compliance, which in turn limit their application in clinical practice. In this study, we propose to establish a personalized exercise prescription based on the Chinese traditional exercise-Yi Jin Jing, combined with treadmill exercises and strength training, and then observe its effects on pain, muscle strength, balance, bone mineral density (BMD) and bone metabolic indexes in patients with POP.

METHODS

This trial is a single-center, randomized, assessor-blinded, controlled clinical study. We will recruit 40 patients with POP and assign them to the control group and the experimental group in a 1:1 ratio according to the intended protocol. The control group received 24 weeks of conventional medication and health promotion, and the experimental group received 24 weeks of personalized exercise prescription intervention (Yijinjing, treadmill exercises, and strength training). Outcome measures include pain (visual analogue scale), muscle strength (bilateral upper limb grip strength and isometric muscle strength of the trunk, hip, and knee), balance (Balance test with eyes open and closed while standing on one leg), and BMD (Lumbar spine 2-4 and femoral neck). In addition, bone metabolism indicators include parathyroid hormone, osteocalcin, 25-hydroxyvitamin D3 (1,25(OH) 2D3), type I procollagen aminoterminal peptide and type I collagen carboxy-terminal peptide. Outcome measures will be assessed before and after 24 weeks of intervention. Statistical analysis was performed by SPSS22.0.

DISCUSSION

This trial aimed to enrich the content and form of exercise rehabilitation prescriptions for patients with POP, which is conducive to improving the exercise rehabilitation effect and quality of life in this population.