Kisspeptin (Kp-10) is a neuropeptide that binds to GPR54 receptors, exerting several functions mainly in the nervous and reproductive systems of the body. However, its effects and mechanisms of action on the skeletal system remain poorly understood. This study evaluated the effects of different concentrations of Kp-10 on in vitro osteogenic differentiation of multipotent mesenchymal stromal cells (MSCs) extracted from the bone marrow (BM) of adult Wistar rats. Two-month-old female rats were euthanized to extract BM from long bones to obtain MSCs. Four experimental groups were established in vitro: a control and Kp-10 at concentrations of 0.01, 0.05 and, 0.1 µg/mL. After induction of osteogenic differentiation, cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)− 2,5-diphenyl tetrazolium bromide (MTT) assay, alkaline phosphatase activity, collagen synthesis, percentage of area covered by MSCs/field and mineralized nodules/field, and immunocytochemistry of the GPR54 receptor tests. Furthermore, evaluation of gene transcripts for type I collagen, Runx-2, Bmp-2, bone sialoprotein, osteocalcin and osteopontin was performed using real-time RT-qPCR. It was observed that MSCs expressed GPR54 receptor to which Kp-10 binds during osteogenic differentiation, promoting a negative effect on osteogenic differentiation. This effect was observed at all the Kp-10 concentrations in a concentration-dependent manner, characterized by a decrease in the activity of alkaline phosphatase, collagen synthesis, mineralized nodules, and decreased expression of gene transcripts for type I collagen, osteocalcin, osteopontin, and Runx-2. Thus, Kp-10 inhibits in vitro osteogenic differentiation of MSCs extracted from the BM of adult Wistar rats.

Kisspeptin (Kp-10) 是一种与 GPR54 受体结合的神经肽，主要在身体的神经和生殖系统中发挥多种功能。然而，它对骨骼系统的影响和作用机制仍然知之甚少。本研究评估了不同浓度的 Kp-10 对从成年 Wistar 大鼠骨髓 (BM) 中提取的多能间充质基质细胞 (MSC) 体外成骨分化的影响。将两个月大的雌性大鼠安乐死，从长骨中提取骨髓以获得间充质干细胞。体外建立了四个实验组：对照组和浓度为 0.01、0.05 和 0.1 µg/mL 的 Kp-10。诱导成骨分化后，使用 3-(4,5-二甲基噻唑-2-基)− 2,5-二苯基溴化四唑 (MTT) 测定评估细胞活力、碱性磷酸酶活性、胶原合成、被覆盖的面积百分比MSC/视野和矿化结节/视野，以及 GPR54 受体测试的免疫细胞化学。此外，使用实时 RT-qPCR对 I 型胶原、Runx-2、Bmp-2 、骨唾液蛋白、骨钙素和骨桥蛋白的基因转录本进行了评估。据观察，MSCs 表达 GPR54 受体，Kp-10 在成骨分化过程中与其结合，促进对成骨分化的负面影响。在所有 Kp-10 浓度下均以浓度依赖性方式观察到这种效应，其特征是碱性磷酸酶活性、胶原合成、矿化结节降低，以及 I 型胶原、骨钙蛋白、骨桥蛋白、和Runx-2。因此，Kp-10 抑制从成年 Wistar 大鼠骨髓中提取的 MSC 的体外成骨分化。