Abstract: AIM: To study the effects of arsenolite on the leukotriene C₄ and the expression of cPLA₂ mRNA in ovalbumin challenged asthmatic mice. METHODS: 56 mice were randomly divided into 7 groups. Establishing the ovalbumin sensitized asthmatic model, RT-PCR was employed to detect the expression of cPLA₂ mRNA in the lung. The TLC₄ and PLA₂ in BALF were measured by ELISA. Expiration time /respiratory total time and expiration maximum pressure were detected. RESULTS: The expression of PLA₂ mRNA in the lung and the TLC₄, PLA₂ activity in BALF in asthmatic group were significantly higher than those in normal group. After therapy with dexamethasone and different dosage of arsenolite (0.625, 1.25, 2.and 5.00 mg·kg^-1), the expression of PLA₂ mRNA and the TLC₄, PLA₂ activity were significantly lower than those in asthmatic group. Expiration time /respiratory total time and expiration maximum pressure in asthmatic group were significantly increased compared with normal group. Expiration time /respiratory total time and expiration maximum pressure of groups treated with 4 doses arsenolite were significantly decreased compared with asthmatic group. CONCLUSION: PLA₂ mRNA expression increases in asthma group, and arsenolite can efficiently treat asthma. Its mechanism maybe partly relates to decreasing TLC₄ in airway and the inhibition of PLA₂ mRNA expression.

Key words: arsenolite, arsenic trioxide, asthma, cytoplastic phospholipases A₂