In vitro maturation (IVM), an alternative to in vivo maturation before fertilisation, attracts increasing attention because of its potential applications. This technique has been widely used for medical purposes and livestock production, given its advantages over traditional in vitro fertilisation (IVF), such as shorter stimulation cycles, fewer injections and lower costs of related drugs and monitoring. However, external factors, such as pH, osmotic pressure, temperature and gas composition, can disrupt the embryonic environment and the balance between nuclear and cytoplasmic development, affecting the quality of fertilised embryos [1,2].

Under normal physiological conditions, the oxidant defence system in cells maintains an oxidant–antioxidant balance. However, oxidative stress occurs when oxidative substances produced in response to related stressors overwhelm the antioxidant system. Studies have shown that oxidative stress is one of the important causes of female reproductive disorders. Oxidative stress can induce the deformation and even the apoptosis of oocytes, altering the meiotic spindle and stimulating lipid peroxidation, selective disappearance of cell membranes, inactivation of cytosolic enzymes and DNA damage.

Reactive oxygen species (ROS) are oxygen‐free radicals released by aerobic metabolism in the mitochondrial electron transport chain. As a critical player in cell signalling, receptor activation and gene expression, ROS at normal cellular concentrations can stabilise the physiological state of oocytes. However, at supraphysiological concentrations, ROS can trigger oxidative stress and cause RNA, DNA and protein oxidation, disturbance of membrane integrity and shortening of telomere length and can ultimately lead to functional damage to oocytes [3].

Medium supplements for IVM have been introduced to improve oocyte quality, maintain the balance between oxidative stress and antioxidant activity in embryos and strengthen the antioxidant ability of embryos. These supplements mostly support IVM by upregulating the function of sirtuin1 (SIRT1), which increases mitochondrial activity [4] potentially by promoting mitochondrial biosynthesis and degradation through mitosis and stabilising the mitochondrial membrane potential in oocytes.

Dendrobium nobile extract (DNE), a key active ingredient of noble dendrobium (Dendrobium nobile), is composed of sesquiterpene alkaloids and has anti‐inflammatory, antioxidant [4], antiaging [5] and immunomodulatory properties [6]. Research has shown that DNE can protect the skin from oxidative stress by modulating the antioxidant system [7]; Given its ability to inhibit apoptosis by upregulating B‐cell lymphoma 2 (Bcl‐2) and downregulating Bcl‐2 associated X (Bax), DNE is considered to have neuroprotective activity.

The above findings infer that DNE potentially improves oocyte quality and post‐fertilisation embryonic development through oxidative stress suppression and oocyte apoptosis regulation. On this basis, this study investigated the effects of DNE on oocyte quality and embryonic development in the context of IVF using the IVM technique. The study evaluated the maturation and development levels of oocytes and embryos, measured the spindle assembly, DNA damage and changes in matrix metalloproteinase (MMP), ROS, and glutathione (GSH) levels during oocyte maturation, and analysed the expression levels of oxidative stress‐ and apoptosis‐inducible genes.

The discussed findings imply that DNE might enhance oocyte quality and post-fertilisation embryo development by inhibiting oxidative stress and regulating apoptosis in oocytes. Therefore, we investigated the effect of DNE on the quality of IVM oocytes and the development of embryos through IVF. First, we examined oocyte maturation and embryonic development. Subsequently, we measured the changes in MMP, ROS and GSH content during oocyte maturation and analysed the changes in the expression of genes related to oxidative stress and apoptosis induction.