Effects and Mechanism of Berberine on the Dexamethasone‐Induced Injury of Human Tendon Cells

Abstract

Objective. To investigate the effects of berberine (Berb) on dexamethasone- (Dex-) induced injury of human tendon cells and its potential mechanism. Methods. CCK-8 assay was used to explore the appropriate concentration of Dex-induced injury of tendon cells and the doses of Berb attenuates Dex cytotoxicity; cell wound healing assay was used to detect the effects P < 0.05 of Berb and Dex on the migration ability of tendon cells; flow cytometry was used to measure cell apoptosis; DCF DA fluorescent probe was used to measure the ROS activity of cells. Western blotting was used to detect the expression of phenotype related factors including smooth muscle actin α (SMA-α), type I collagen (Col I), col III, apoptosis-related factors, caspase-3, cleaved caspase-3, caspase-9, cleaved caspase-9, and PI3K/AKT. Results. CCK-8 assay showed that 1–100 μM Dex significantly inhibited the proliferation of tendon cells in a concentration-dependent manner P < 0.05 , where the inhibitory effect of 100 μM Dex was most significant P < 0.005 , and the pretreatment of 150, 200 μM Berb could reverse those inhibitions (all P < 0.05 ). Compared with the control group, Dex significantly inhibited cell migration P < 0.05 , while Berb pretreatment could enhance cell migration P < 0.05 . Flow cytometry and ROS assay showed that Dex could induce apoptosis and oxidative stress response of tendon cells (all P < 0.05 ), while Berb could reverse those responses P < 0.05 . Western blot showed that Dex could inhibit the expression of the col I and III as well as α-SMA (all P < 0.05 ) and enhance the expression of apoptosis-related factors including cleaved caspase-3 and cleaved caspase-9 (all P < 0.05 ). Besides, Dex could also inhibit the activation of the PI3K/AKT signaling pathway (all P < 0.05 ), thus affecting cell function, while Berb treatment significantly reversed the expression of those above proteins (all P < 0.05 ). Conclusion. Berb attenuated DEX induced reduction of proliferation and migration, oxidative stress, and apoptosis of tendon cells by activating the PI3K/AKT signaling pathway and regulated the expression of phenotype related biomarkers in tendon cells. However, further studies are still needed to clarify the protective effects of Berb in vivo.

Roles of Oxidative Stress in Acute Tendon Injury and Degenerative Tendinopathy—A Target for Intervention

“…A single peritendinous injection of bupivacaine increased apoptosis of endotenon cells, increased pro-MMP-9 expression, increased the type III collagen/type I collagen ratio, and transiently reduced the tensile load of the affected Achilles tendon in rats [ 80 ]. Dexamethasone induced oxidative stress in tendon cells, along with reduced cell migration, proliferation, types I and type III collagen expression as well as activation of apoptosis [ 81 ]. In another study, dexamethasone was also reported to reduce proliferation and tenogenic marker expression in tenocytes in vitro [ 82 ].…”

“…Berberine is an antioxidant found in some plants, such as European barberry, goldenseal, goldthread, Oregon grape, phellodendron, and tree turmeric. Treatment with berberine reversed the effects of dexamethasone on tendon cells [ 81 ]. Oral administration of chloroform extract of Azadirachta indica and methanolic extract of Cuminum cyminum was shown to reduce oxidative stress and collagen cross linking in rat tail tendon in streptozotocin-induced diabetic rats [ 109 , 110 ].…”