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.

OBJECTIVE To explore the effect and mechanism of Zhiqiao gancao decoction （ZQGCD） on pathological angiogenesis of degenerative intervertebral disc. METHODS The rats were randomly divided into sham operation group （normal saline）， model group （normal saline）， hypoxia inducible factor-1α （HIF-1α） inhibitor （YC-1） group [2 mg/（kg·d）， tail vein injection]， and ZQGCD low-dose， medium-dose and high-dose groups [3.06， 6.12， 12.24 g/（kg·d）]， with 8 rats in each group. Except for sham operation group， lumbar disc degeneration model of rat was constructed in all other groups. After modeling， they were given relevant medicine once a day， for consecutive 3 weeks. After the last medication， pathological changes and angiogenesis of the intervertebral disc tissue in rats were observed； the levels of inflammatory factors [interleukin-1β （IL-1β）， IL-6， tumor necrosis factor-α （TNF-α）] and the expressions of angiogenesis-related proteins [HIF-1α， vascular endothelial growth factor （VEGF）， VEGF receptor 2 （VEGFR2）， angiotensin 1（Ang 1）， Ang 2] in the com intervertebral disc tissue in rats were all determined. In cell experiment， the primary nucleus pulposus cells were isolated and cultured from rats， and cellular degeneration was induced using 50 ng/mL TNF-α. The cells were divided into blank control group （10% blank control serum）， TNF-α group （10% blank control serum）， YC-1 group （10% blank control serum+0.2 mmol/L YC-1）， and 5%， 10%， 15% drug-containing serum group （5%， 10%， 15% drug-containing serum）. After 24 hours of intervention， the nucleus pulposus cells were co-cultured with HUVEC. The expressions of Collagen Ⅱ， matrix metalloproteinase-3 （MMP-3） in nucleus pulposus cells were detected. HUVEC proliferation， migration and tube forming ability were detected， and the expression levels of the HIF-1α/VEGF/Ang signal axis and angiogenesis- related proteins （add MMP-2， MMP-9） in HUVEC were detected. RESULTS Animal experiments had shown that compared with model group， the positive expression of CD31 in the intervertebral disc tissues of rats in each drug group was down-regulated （P＜ 0.05）， the levels of inflammatory factors and angiogenesis-related proteins were decreased significantly （P＜0.05）， and the pathological changes in the intervertebral disc were alleviated. Cell experiments had shown that compared with TNF-α group， the expression of Collagen Ⅱ in nucleus pulposus cells of all drug groups was significantly up-regulated （P＜0.05）， and the expression of MMP-3 was significantly down-regulated （P＜0.05）； the proliferation， migration and tubulogenesis of HUVEC were significantly weakened （P＜0.05）. The mRNA and protein expressions of HIF-1α， VEGF， Ang 2 as well as the expression of angiogenesis-related proteins （except for the expression of Ang 2 mRNA and HIF-1α， VEGFR2， Ang 2 protein in 5% drug- containing serum group） were significantly down-regulated （P＜0.05）. CONCLUSIONS ZQGCD may inhibit the HIF-1α/VEGF/ Ang signal axis to weaken the angiogenic ability of vascular endothelial cells， improve pathological angiogenesis in the intervertebral disc， and delay the degeneration of the intervertebral disc.