Objective To observe the effect of warm dryness on th e ultra-structure

function and mucin gene expression of the lung tissue.Methods Seventy eight Ku nming mice were randomized into the normal temperature and humidity group

norma l warm dryness group and warm dryness group

with 26 in each.The models were es tablished with the stimulation of temperature

relative humidity and wind.On th e 6th and 12th day of modeling

the ultra-structure of respiratory membrane and type Ⅱ alveolar cell（ATⅡ）

the expression of lung mucin gene 5ac（Muc 5ac）

an d the level of nuclear factor kappa-light-chain-enhancer of activated B cells （N F-κB）

tumor necrosis factor-α（TNF-α） and dipalmitoyl phosphatidyl cholin e（ DPPC） were observed.Results Comparing with the normal temperature and humidity group

the number of osmiophilic multilamellar body（OMB） was reduced and mitoch ondria（M） showed swelling in the normal warm dryness group on the 12th day of m odeling.In the warm dryness group

the junction of type Ⅰalveolar cell（ATⅠ） and ATⅡ showed swelling and resulted in disorganized microvilli and declining O MB in ATⅡ on the 6th day of modeling.On the 12th day of modeling

membrane thi ckening

significantly declining of OMB in ATⅡ and declining and swelling of M were observed in the warm dryness group.The average area of OMB in ATⅡ and the activity of NF-κB reduced（P<0.05 or P<0.01）

the level of DPPC dec reased（P<0.01）

the expression of Muc 5ac gene increased and the expression of TNF-α decr eased（P<0.05） on the 6th and 12th day of modeling in the normal warm drynes s gro up and warm dryness group.Comparing with the normal warm dryness group at the s ame time point

the average area of OMB and the level of DPPC and TNF-α decrea s ed significantly in the warm dryness group on the 6th and 12th day of modeling（ P <0.05）.Conclusion Warm dryness damaging the lung coul d result in the disorders of energy metabolism and impaired secretion of pulmonary surfactant in ATⅡ

th e increasing expression of Muc 5ac gene

the decreasing activity of NF-κB and T NF-α

thickening respiratory membrane and pulmonary dysfunction.The activity o f NF-κB

TNF-α and DPPC could be used as the characteristic indicators for mo lecular pathogenesis of warm dryness damaging the lung.