Relationships between factors of nonspecific resistance in shock caused by mechanical trauma or burn

Abstract

Rats with shock caused by mechanical injury or burn showed stereotypic and phasic variations of the absorptive capacity of hepatic reticuloendothelial system, plasma fibronectin content, and functional activity of peripheral blood neutrophils. The direction of alterations in these factors of nonspecific resistance pointed to a depression of the phagocytic system and correlated with the severity of the postinsult states.Key Words: shock; macrophages; neutrophils; fibronectin; phagocytosisThe phagocytic system plays an important role among the factors of nonspecific resistance which are largely responsible for adaptational changes occurring in the body after mechanical or thermal injury. There is convincing evidence that shock induces pronounced changes in the morphology and function of neutrophils and macrophages in some humoral factors. Special attention was focused on fibronectin (FN), a nonspecific opsonin of blood plasma [2,11,12,14,15]. Previously, we showed that the response to severe mechanical or thermal trauma involves a considerable decrease in plasma FN content and pronounced suppression the hepatic clearance provided by the reticuloendothelial system (RES), which is accompanied by destruction of stellate reticuloendothelial cells [9,10]. As we are aware, there is no literature data on the relationship between cellular and humoral factors of phagocytosis in shock. Thus, a question arises: how homeostasis is maintained after shock-producing injury? Therefore, we analyzed temporal changes in some factors of nonspecific resistance in animals after injury. MATERIALS AND METHODS Shock was induced in rats under light Hexenal anesthesia by the method of Cannon (traumatic shock)Department of Forensic Medicine, State Medical University, Kazan and the method of Kochetygov (burn shock). Plasma FN content was measured by enzyme immunoassay [3], gelatin-binding capacity of FN was determined as described [6], and the functional state of neutrophils was assessed by their phagocytic activity, phagocytic index, and their total and differential counts [1] 1-72 h after induction of shock. The absorptive capacity of hepatic RES was assessed by the clearance of gelatinized particles of casein ink [8] with determination of their elimination half-life and elimination rate constant. The results were statistically analyzed by parametric methods. RESULTSOur study confirmed that two types of reaction develop in response to a limited mechanical or thermal injury [9]. In 15-20% of rats, relatively mild shock and rapid stabilization of clinical and physiological parameters (type I reaction) were observed. Severe shock with increasing manifestations of multisystem insufficiency (type II) was observed in other rats, which had a low level of nonspecific defense.In rats with severe shock, the phagocytic function of hepatic RES was markedly suppressed. The blood clearance rate constant at the height of the torpid phase being only about 50% of the baseline value (Fig. 1). Blood content of immunoreactive and biologically active FN was redu...

Effect of phagocyte stimulation on nonspecific organism's resistance to shock

“…It has been shown that macro-and microphage suppression against the background of hypofibronectinemia reflects the severity of postaggressive states and usually disappears in natural relieve of the shock [4][5][6]. These findings agree with the published data that organism's resistance to extreme factors strongly depends on the functional state of the phagocytosis system and plasma opsonizing activity [2,9,10,12,15].…”