In prior studies, we and others have documented a significant reduction by surface chemistry modification in the
biological activity of
quartz. We further documented that
aluminium lactate inhalation one month after
quartz exposure significantly suppressed the
silica-induced alveolitis, reduced the pathological process and decreased the retention of
quartz in the lung tissue. In the present study, we evaluated the efficacy of
aluminium inhalation in altering the
silicosis process after disease was recognized by standard chest radiography. Twenty-four sheep were enrolled in the study. The 14
silica exposed sheep had an abnormal chest radiograph of the ILO category 1 or above after 3 years of 100 mg Minusil-5 in 100-ml saline intratracheal
injections. Ten control sheep were exposed to saline intratracheal
injections. All sheep were evaluated at 3-month intervals by chest radiography, lung function and lung lavage. At month 36 of the study, all 14 sheep had an abnormal chest radiograph while the radiographs of controls remained normal. The sheep with
silicosis had significantly reduced lung functions and increased cellularity,
phospholipids and
hyaluronan. These changes persisted during the next 12 months without exposure or treatment. At month 48 and at monthly intervals after, for 12 months,
aerosol inhalations were carried out with saline alone for control and seven silicotic sheep and with 100 mg of
aluminium lactate in 10 ml saline generated with a Bird Mark 8 pressure
ventilator for the other seven silicotic sheep. All sheep were evaluated at 3-month intervals by chest radiography, lung function and lung lavage.(ABSTRACT TRUNCATED AT 250 WORDS)