[Immune complex may play an important role in freezing injury of frostbite rats]

To explore the role of humoral immunity in the pathophysiological process of freezing injury and the possible immune interference in the preventation and treatment of frostbite.

Severe experimental freezing injury model was made in Wistar rats( n = 20). The concentration of three types of immunoglobulin (IgG, IgA and IgM), two types of complement components (C3 and C4), and circulating immune complex (CIC) were measured respectively before and at 4h, 1d, 3d, and 5d after frostbite. At the same time, the tissue immune complex (TIC) in skeletal muscle and the contents of the red blood cell immune complex (RBC-IC) were also observed and then was the red blood cell immune adherence activity (RCIA).

Serum IgG concentration decreased rapidly to the lowest level at 4 h after frostbite IgA concentration dropped to the nadir on 1 day after freezing. Decreases of both immunoglobulins were maintained during the 5 days after frostbite. The fate of both C3 and C4 were the same as those immunoglobulins. Freezing had rather less effect on IgM level. CIC concentration in serum, expressed as the percent of prefreezing increased rapidly and to the zenith on the 3 days post-freezing. By immunofluorescence microscopy, thin continuous linear pattern (IgG) was demonstrated along the SM on the first day post-freezing. Granular and nodular deposits (IgG) appeared along the SM as the time proceeded after frostbite. RBC-IC contents, expressed as the erythrocyte IC rosette rate, increased significantly and to the zenith on the 3 d post-freezing, while RCIA depressed to the nadir at the same time.

The freezing frostbite is an immune complex related disease which have not been reported by others before.