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Considerable attention has recently focused on the role of inflammation in the pathophysiology of asthma, with special emphasis on "late-phase" bronchoconstriction and increased airway hyperreactivity after antigen challenge in sensitized subjects. The present report describes the histopathologic changes in guinea-pig lung and trachea at various time intervals after ovalbumin inhalation in nonsensitized (control) and sensitized animals. Bronchoalveolar lavage (BAL) was also used to assess the accompanying accumulation of intraluminal leukocytes. A distinct leukocyte margination, consisting of neutrophils and eosinophils, was observed in the peribronchial vasculature as early as 8 min postchallenge in sensitized guinea pigs. At 6 h, the eosinophils predominated and migrated to the peribronchiolar smooth muscle layer. Between 6 h and 18 h, eosinophils were seen in tracts between the smooth muscle cell layers, accumulating in large numbers in the bronchial mucosal epithelium. This pattern persisted for at least 7 days postchallenge during which eosinophils remained the dominant cell type present. Peribronchiolar accumulation of neutrophils and mononuclear cells was minimal at all time points studied. Intraluminal mucus eosinophilia developed between 18 h and 7 days. A similar pattern of eosinophil infiltration was observed in the tracheal epithelium. Control, nonsensitized, guinea-pig lungs showed minor changes with little or no eosinophil infiltration at any time after antigen challenge. These findings correlated well with the BAL study in which sensitized guinea pigs exhibited a marked delayed increase in eosinophil counts between 18 h and 7 days compared with that in nonsensitized animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Transgenic mice that overexpress a mutated human CuZn superoxide dismutase (SOD1) gene (gly93-->ala) found in some patients with familial ALS (FALS) have been shown to develop motor neuron disease, as evidenced by motor neuron loss in the lumbar and cervical spinal regions and a progressive loss of voluntary motor activity. The mutant Cu,Zn SOD exhibits essentially normal dismutase activity, but in addition, generates toxic oxygen radicals as a result of an enhancement of a normally minor peroxidase reaction. In view of the likelihood that the manifestation of motor neuron disease in the FALS transgenic mice involves an oxidative injury mechanism, the present study sought to examine the extent of lipid peroxidative damage in the spinal cords of the TgN(SOD1-G93A)G1H mice over their life span compared to nontransgenic littermates or transgenic mice that overexpress the wild-type human Cu,Zn SOD (TgN(SOD1)N29). Lipid peroxidation was investigated in terms of changes in vitamin E and malondialdehyde (MDA) levels measured by HPLC methods and by MDA-protein adduct immunoreactivity. Four ages were investigated: 30 days (pre-motor neuron pathology and clinical disease); 60 days (after initiation of pathology, but predisease); 100 days (approximately 50% loss of motor neurons and function); and 120 days (near complete hindlimb paralysis). Compared to nontransgenic mice, the TgN(SOD1-G93A)G1H mice showed blunted accumulation of spinal cord vitamin E and higher levels of MDA (P < 0.05 at 30 and 60 days) over the 30-120 day time span. In the TgN(SOD1)N29 mice, levels of MDA at age 120 days were significantly lower than in either the TgN(SOD1-G93A)G1H or nontransgenic mice. MDA-protein adduct immunoreactivity was also significantly increased in the lumbar spinal cord at age 30, 100, and 120 days, and in the cervical cord at 100 and 120 days. The results clearly demonstrate an increase in spinal cord lipid peroxidation in the FALS transgenic model, which precedes the onset of ultrastructural or clinical motor neuron disease. However, the greatest intensity of actual motor neuronal lipid peroxidative injury is associated with the active phase of disease progression. These findings further support a role of oxygen radical-mediated motor neuronal injury in the pathogenesis of FALS and the potential benefits of antioxidant therapy.