AIM: To determine whether triptolide induce apoptosis of synovial cells in collagen - induced arthritis(CIA) in rats. METHODS: The male Wistar rats were used to make CIA models by immunized with Bovine collagen Ⅱ ( BC Ⅱ )in Freund's complete adjuvant (FCA). A total of 20 CIA rats were randomly divided into 2 groups, triptolide group (10 rats) and CIA control group (10 rats). Triptolide group were administered with triptolide at 40 μg/kg body weight intramuscularly every three days. CIA control group andanother 10 age - matched normal rats were given normal saline instead. The rats were sacrificed on the 31st day after the triptolide administration. The pieces of synovium of the rat knee joints were harvested. The synovium was examined by HE staining and electron microscope. The apoptosis was tested by TUNEL and flow cytometer. RESULTS: The earlier phase of apoptotic synoviocytes were observed under the electron microscope. The flow cytometry showed that the percentage of the apoptotic cells was (3.98 ± 1.16)% in the triptolide group, (1.83 ± 0.82)% in the CIA control group, and (0.87 ±0.24)% in the normal group (P＜0.01: triptolide vs control group). While the percentage of the cells in DNA synthesis phase was (3.3± 1.2)% in the triptolide goup, (8.0± 1.4)% in the CIA control group, and (3.4 ± 0.7)% in the normal group.There is significantly different in the apoptosis changes between the triptolide group and the CIA control group ( P ＜ 0.01: triptolide vs CIA control group). The TUNEL labeling demonstrated that the percentage of the apoptotic cells was (4.5 ± 1.0)% in the triptolide group, (2.2 ± 1.0) % in the CIA control group, and ( 1.0 ± 0.4) % in the normal group. The difference of apoptotic rate between the triptolide group and the CIA control group is significant ( P ＜ 0.01). CONCLUSION: This study demonstrates that triptolide can induce apoptosis in CIA rats, which may be one of the mechanisms that triptolide treats the rheumatoid arthritis.

AIM: To determine whether triptolide induce apoptosis of synovial cells in collagen-induced arthritis (CIA) in rats. METHODS: The male Wistar rats were used to make CIA models by immunized with Bovine collagen Ⅱ (BCⅡ) in Freund's complete adjuvant (FCA). A total of 20 CIA rats were randomly divided into 2 groups, triptolide group (10 rats) and CIA control group (10 rats). Triptolide group were administered with triptolide at 40 ?g/kg body weight intramuscularly every three days. CIA control group and another 10 age-matched normal rats were given normal saline instead. The rats were sacrificed on the 31st day after the triptolide administration. The pieces of synovium of the rat knee joints were harvested. The synovium was examined by HE staining and electron microscope. The apoptosis was tested by TUNEL and flow cytometer. RESULTS: The earlier phase of apoptotic synoviocytes were observed under the electron microscope. The flow cytometry showed that the percentage of the apoptotic cells was (3.98?1.16)% in the triptolide group, (1.83?0.82)% in the CIA control group, and (0.87?0.24)% in the normal group (P