Preventive effect of hochu-ekki-to, a Japanese herbal medicine, on bleomycin-induced lung injury in mice.
ABSTRACT Pulmonary fibrosis is thought to be closely associated with the T-helper type-2 (Th2) immune response. Recent studies have shown that hochu-ekki-to (TJ-41), a Japanese herbal medicine, may correct the Th1/Th2 imbalance skewed to Th2. The present study was designed to investigate the preventive effect of TJ-41 on the development of bleomycin (BLM)-induced lung injury in mice.
Female C57BL/6 mice were divided into a group given ordinary feed and another group given the same feed plus TJ-41 mixed in at a dose of 1 g/kg/day. Both groups were maintained on this diet for 8 weeks before and 5 weeks after administration of 2 mg/kg BLM intratracheally.
Mortality after BLM-induced lung injury was significantly lower in the TJ-41-treated mice. The hydroxyproline content and fluid content in the lung on day 35 was significantly lower in the TJ-41-treated mice. Histologically, TJ-41 reduced the number of infiltrating cells, thus ameliorating the destruction of the lung architecture, and attenuated the lung fibrosis score. Furthermore, TJ-41 inhibited the expression of the interleukin-5/interferon-gamma mRNA ratio in the lung on day 7.
Treatment with TJ-41 partially prevented experimental lung fibrosis through the correction of the Th1/Th2 imbalance skewed to Th2.