The in vivo effects of quartz on rat thoracic lymph nodes.

The histological changes in the regional thoracic lymph nodes of rats exposed to silica dust by inhalation are recorded. A dual response is noted involving both inflammatory and immune mechanisms, resulting in a fibroblastic connective tissue reaction and a plasma-cell-macrophage interaction. It is proposed that the progressive silicotic lesions obstruct the lymphatic channels in the lymph nodes, thus interfering with the lymph drainage from the lung and aggravating the silicotic process in the lung itself.