Ligustrazine Reduces the Apoptosis of Synovial Cells in Knee Arthritis Rats by Inhibiting the Expression of Glucose Regulatory Protein 78 and CCAAT Enhancer Binding Protein Beta (C/EBPb)

Abstract

To investigate the effect of Ligustrazine on synovial cells and expression of GRP78 and C/EBPb in knee arthritis rats, 52 healthy SD rats, aged 10-15 months, weighing 185–225 g, were selected and fed routinely. According to the principle of random distribution, the experimental rats were assigned into healthy group, arthritis group, ligustrazine 1 and 2 groups, with 13 rats in each group. HE staining was used to detect the pathological morphology. Mankin score was used to measure the severity of the disease. The apoptosis of synovial cells was assessed by flow cytometry. col2α1 and VEGF levels were detected by RT-PCR and GRP78, XBP1 and C/EBP β levels were detected by Western blot. In the healthy group, the cells were scattered orderly, the cartilage surface was smooth, and the synovial tissue was not damaged; in the arthritis group, the joint tissue was damaged, the synovial tissue proliferated and degenerated, the cells were disordered, and synovial pannus was produced; in Ligustrazine group 1 and Ligustrazine 2 groups had certain improvement, and the effect to Ligustrazine group 2 was more obvious. Mankin score of healthy group was lower than arthritis group (P < 0.05) which had higher Mankin score than Ligustrazine 1 and 2 groups, and the Mankin score of Ligustrazine 2 group was lower than that of Ligustrazine 1 group (P < 0.05). Synovial cells apoptosis in healthy group was lower than arthritis group (P < 0.05) which had higher apoptosis than Ligustrazine 1 group and ligustrazine 2 group (P < 0.05) with lower apoptosis for Ligustrazine 2 group (P < 0.05). The expressions of col2α1 mRNA and VEGF mRNA in healthy group were lower than arthritis group (P < 0.05) which had higher levels than Ligustrazine 1 and 2 groups with Ligustrazine 2 group showing more obvious effects (P < 0.05). Arthritis group had significantly elevated levels of GRP78 and XBP1 and decreased C/EBP β levels (P < 0.05). However, GRP78 and XBP1 levels in TMP-1 group and tmp-2 group were decreased and C/EBP β level was increased (P < 0.05). In a word, Ligustrazine can reduce the apoptosis of synovial cells, promote the repair of cartilage tissue and improve the condition of knee arthritis rats by regulating the expression level of GRP78 and XBP1.