Abstract: Objective: To observe the effects of ligustrazine hydrochloride injection(LHI) on pulmonary arterial hypertension in chronic obstructive pulmonary disease(COPD) patients and to investigate its possible mechanisms. Methods: Twenty-two cases of patients with COPD were randomly divided into conventional treatmentgroup (group C) and ligustrazine treatment group(group L), 11 persons were randomly selected from healthy subjects without lung disease served as normal control group(group N). Group C was given bed rest, low flow oxygen inhalation, bronchial diastolic agent, glucocorticoid and antibiotics and other conventional treatment, and group L was added with ligustrazine hydrochloride injection on the above mentioned basis treatment, group N was given no treatment. After 2 weeks, lung function, blood gas analysis and pulmonary arterial pressure were compared among the three groups, and the content of H₂S in plasma was tested with sensitive sulfur electrode method. Results: ①After two weeks treatment, in group L and group C pulmonary function, blood gas analysis, pulmonary artery pressure were obviously improved, and group L was better than group C (P<0.05); ② In group L the content of H₂S was increased (P<0.01), group C had no significant difference (P>0.05), and there was a significant difference between the two groups (P<0.01). Conclusion: Combination with LHI can effectively improve lung function. LHI mayrelieve hypoxic hypercapnia pulmonary hypertension induced by COPD through raising the content of H₂S.

Key words: ligustrazine hydrochloride injection, pulmonaryarterial hypertension, hypoxia-hypercapnia, COPD, H₂S