STUDY ON APOPTOSIS OF HUMAN MAST CELLS INDUCED BY TRIPTERINE

Bao Y-X¹, Zhang D-H²

¹Xinhua Hospital, Shanghai, China

²Eastern Hospita, Shanghai, China

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Objective: To explore the effect and mechanism of tripterine in induction of human mast cell apoptosis.

Methods: Taking mast cells from nasal polyps and the human mast cell line (HMC-1) cells as targets, apoptosis was detected by observing the changes in morphology, DNA electrophoresis, flowcytometric (FCM) analysis and TUNEL. The expression of apoptosis related genes such as bcl-2, bax, c-myc were evaluated by immunohistochemistry and semi-quantative RT-PCR methods. Intracelluar plasmic free Ca²⁺ concentration was analysed by FCM.

Results: 1. On the exposure to tripterine (1.0mmol/L) for 12hr, apoptosis of mast cells in nasal polyps tissue could be seen and the number of mast cells decrease significantly. 2.Apoptosis of HMC-1 cells could be efficiently induced by tripterine (0.125-1.0mmol/L), with the presence of apoptotic changes in morphology, DNA Ladder on argrose gel electrophoresis and apoptotic peak before G₁ phase of cell cycle on FCM. On the condition of 1.0mmol/L tripterine, apoptosis started at 20min and reached 89% at 12 hr. The magnitude of apoptosis increased with the augmentation of tripterine concentration and duration of tripterine exposure. Apoptotic cells increased with diminution of S phase cells. They bore significant relation (P<0.01). 3.Apoptosis of HMC-1 cells were accompanied by bax protein up-regulated and bcl-2 protein down-regulated, Bax especially bcl-2 mRNA down-regulated.4. On exposure to tripterine intracelluar plasmic free Ca²⁺ concentration of HMC-1 cells was quickly elevated, which could be inhibited by EDTA. EDTA could also inhibit HMC-1 cells apoptosis induced by tripterine.

Conclusion: Mast cells from nasal polyps and the human mast cell line (HMC-1) cells can be apoptotosis induced by tripterine .The apoptosis of HMC-1 cells is dose and time dependent and regulated by apoptosis related genes. Ca²⁺ may be its signal transduction molecule.

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