1.The Effect of Zhiqiao Gancao Decoction (枳壳甘草汤) on Intervertebral Disc Nucleus Pulposus Cell Apoptosis and the Hippo-YAP/TAZ Signaling Pathway in Tail Intervertebral Disc Degeneration Model Rats
Zaishi ZHU ; Zeling HUANG ; Junming CHEN ; Bo XU ; Binjie LU ; Hua CHEN ; Xingxing DUAN ; Yuwei LI ; Xiaofeng SHEN
Journal of Traditional Chinese Medicine 2025;66(5):509-517
ObjectiveTo investigate the possible mechanism by which Zhiqiao Gancao Decoction (枳壳甘草汤, ZGD) delays intervertebral disc degeneration (IDD) based on the Hippo-yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) signaling pathway. MethodsA total of 50 SD rats were randomly divided into sham surgery group, model group, low-dose ZGD group, high-dose ZGD group, and high-dose ZGD + inhibitor group, with 10 rats in each group. In the sham surgery group, the rats were pierced in the skin and muscle at the Co6/7/8 segments of the tail with a 21G needle (depth approximately 2 mm) without damaging the intervertebral disc. In the other groups, rats were injected with a 21G needle at the Co6/7/8 segments of the tail to establish an IDD model by piercing the tail intervertebral disc 5 mm. One week after modeling, rats in the low-dose and high-dose ZGD groups were given 6.24 and 12.24 g/(kg·d) of the decoction via gastric gavage, respectively. The high-dose ZGD + inhibitor group was given 12.24 g/(kg·d) of the decoction and an intraperitoneal injection of YAP/TAZ inhibitor Verteporfin 10 mg/kg. The sham surgery and model groups were given 5 ml/(kg·d) of normal saline via gavage. The gavage was given once a day, and the intraperitoneal injection was given every other day. After 4 weeks of continuous intervention, the pathological changes of the tail intervertebral discs were observed using HE staining, Oil Red O-Green staining, and Toluidine Blue staining. Immunohistochemistry was used to detect the expression of aggrecan and MMP3 in the nucleus pulposus. TUNEL fluorescence staining was performed to detect apoptosis in the nucleus pulposus, and the apoptosis rate was calculated. Western blot was used to detect the Hippo-YAP/TAZ signaling pathway, including YAP, phosphorylated YAP (p-YAP), phosphorylated MST1/2 (p-MST1/2), phosphorylated TAZ (p-TAZ) and apoptosis-related proteins, such as Cleaved Caspase 3, P53, Bcl-2 and Bax. ResultsCompared with sham surgery group, the rats in the model group showed significant degenerative changes in the intervertebral disc. The levels of aggrecan, Bcl-2, and YAP proteins in the nucleus pulposus decreased, while the levels of p-MST1/2, p-YAP, p-TAZ, P53, Bax, Cleaved Caspase 3, MMP3 proteins, and the apoptosis rate increased (P < 0.01). Compared with the model group, the drug intervention groups showed partial recovery in intervertebral disc degeneration. The levels of aggrecan, Bcl-2, and YAP proteins increased, while the levels of p-MST1/2, p-YAP, p-TAZ, P53, Bax, Cleaved Caspase 3, MMP3 proteins, and the apoptosis rate decreased (P<0.05 or P<0.01). The high-dose ZGD group showed more significant recovery in intervertebral disc degeneration compared to the low-dose ZGD group, with a decrease in the levels of p-MST1/2, p-YAP, p-TAZ, P53, Bax, Cleaved Caspase 3, MMP3 proteins, and apoptosis rate, and an increase in the levels of aggrecan, Bcl-2, and YAP proteins (P<0.05 or P<0.01). Compared with the high-dose ZGD group, the high-dose ZGD + inhibitor group showed a reduced recovery in intervertebral disc degeneration, with an increase in the levels of p-MST1/2, p-YAP, p-TAZ, P53, Bax, Cleaved Caspase 3, MMP3 proteins, and apoptosis rate, and a decrease in the levels of aggrecan, Bcl-2, and YAP proteins (P<0.05 or P<0.01). ConclusionZGD may delay intervertebral disc degeneration by inhibiting the phosphorylation of YAP in the nucleus pulposus, maintaining the function of the Hippo-YAP/TAZ signaling pathway, and reducing apoptosis of nucleus pulposus cells.