Immunotoxicity assessment of cadinene sesquiterpenes from Eupatorium adenophorum in mice

Sesquiterpenes in Eupatorium adenophorum are abundant in leaves and have great development potential as biopesticides. The toxicity of sesquiterpenes in immune cells and their corresponding immune functions are not fully understood. We evaluated the immunotoxicity of two cadinene sesquiterpenes 2-deoxo-2-(acetyloxy)-9-oxoageraphorone(DAOA) and 9-oxo-10,11-dehydro-agerophorone(ODA) by using histopathology and toxicology methods in vitro and in vivo in lymphocytes and natural killer cells in Kunming mice. The mice were given single doses of 75, 150 and 300 mg kg-1 body weight(BW) of DAOA/ODA every day for a week. S erious damage to the thymus and spleen was found in tissue images with clear lysis reduction numbers and a loosened arrangement of splenocytes and thymocytes to the mice treated with 150–300 mg kg-1DAOA/ODA. Mice cytology was also affected with significant cellular alterations, increased splenocytes apoptosis rates(P<0.01), proliferation reduction(P<0.05) and natural killer cells activities reduction(P<0.05) when given 150–300 mg kg-1DAOA/ODA, the severities of which were dose-dependent. Howev er, a 75 mg kg-1 dose of DAOA/ODA showed no change in tissue or cytology after the 7 day treatment, and therefore was considered to be within acceptable safety parameters. Taken together, cadinene sesquiterpenes, as a type of toxic botanical component, have low environmental risks in small doses and should be further studied for their use as biopesticides.

A comparative study of autogenous, allograft and artificial bone substitutes on bone regeneration and immunotoxicity in rat femur defect model

Repair and reconstruction of large bone defect were often difficult,and bone substitute materials,including autogenous bone,allogenic bone and artificial bone,were common treatment strategies.The key to elucidate the clinical effect of these bone repair materials was to study their osteogenic capacity and immunotoxicological compatibility.In this paper,the mechanical properties,micro-CT imaging analysis,digital image analysis and histological slice analysis of the three bone grafts were investigated and compared after different time points of implantation in rat femur defect model.Autogenous bone and biphasic calcium phosphate particular artificial bone containing 61.4% HA and 38.6%β-tricalcium phosphate with 61.64%porosity and 0.8617±0.0068 g/cm^(3) den-sity(d≤2 mm)had similar and strong bone repair ability,but autogenous bone implant materials caused greater secondary damage to experimental animals;allogenic bone exhibited poor bone defect repair ability.At the early stage of implantation,the immunological indexes such as Immunoglobulin G,Immunoglobulin M concentration and CD4 cells'population of allogenic bone significantly increased in compared with those of autologous bone and artificial bone.Although the repair process of artificial bone was relatively inefficient than autologous bone graft,the low immunotoxicological indexes and acceptable therapeutic effects endowed it as an excellent alter-native material to solve the problems with insufficient source and secondary trauma of autogenous bone.

Counting CD4^(+) and CD8^(+) T cells in the spleen: a novel in vivo method for assessing biomaterial immunotoxicity

As immunotoxicity assessments of newly developed biomaterials are often restricted to use in assessment of local tissue response at the implantation site,they do not always show an immune response acceptable to qualify them for clinical use.We tested a new method to assess systemic toxicity:counting the CD4^(+) and CD8^(+) cells in the spleen.Three different biomaterials were subcutaneously implanted in three groups of rats for the same time period.After 31 days,their spleens were harvested,and CD4^(+) and CD8^(+) cells were counted.The mean CD4^(+)/CD8^(+) cell counts were 24.563.6/19.864.0(porous collagen matrix group),25.567.1/21.663.8[synthetic collagen matrix(DuragenVR)group]and 28.164.1/19.663.7(porcine dermis group).Differences in cell counts were not significant.The immunotoxic response generated against porous collagen matrix was comparable to that produced by a similar biomaterial already used clinically.This is,to the best of our knowledge,the first study on cytotoxic lymphocytes in the spleen to quantify systemic immune response to a biomaterial;however,such studies have been conducted with bacterial and viral antigens,and with vaccines.We believe that the present study provides a viable method for larger studies to confirm our current findings.

Gastrointestinal toxicity induced by microcystins

Microcystins(MCs) are produced by certain bloomforming cyanobacteria that can induce toxicity in various organs, including renal toxicity, reproductive toxicity, cardiotoxicity, and immunosuppressive effects. It has been a significant global environmental issue due to its harm to the aquatic environment and human health. Numerous investigators have demonstrated that MC exposure can induce a widespread epidemic of enterogastritis with symptoms similar to food poisoning in areas close to lakes. Both in vivo and in vitro studies have provided evidence of positive associations between MC exposure and gastrointestinal toxicity. The toxicity of MCs on the gastrointestinal tract is multidimensional. MCs can affect gastrointestinal barrier function and shift the structure of gut microbiota in different gut regions. Furthermore, MCs can inhibit the secretion of gastrointestinal digestive enzymes and the release of inflammatory cytokines, which affects the expression of immune-related genes in the intestine. The damage of the intestine is closely correlated to MC exposure because the intestine is the main site for the digestion and absorption of nutrients. The damage to the gastrointestinal tract due to MCs was summarized from different aspects, which can be used as a foundation for further exploration of molecular damage mechanisms.

Suppression of immunity by some pesticides, xenobiotics, and industrial chemicals. <i>In vitro</i>model

In recent years, attention has focused on suppression of immunity in immunocompromised patients. The definition of immunocompromise is impairment of the immune system caused by a disease or treatment. In addition to disease and treatment, other factors such as exposure to pesticides or toxic chemicals can damage the immune system. An in vitro test was used to assess the ability of monochloroacetic acid (MCA) (CAS number 79-11-8), dichloroacetic acid (DCA) (CAS number 79-43-6), trichloroacetic acid (TCA) (CAS number 76-03-9), and 2,2- dichloropropionic acid sodium salt (2,2-DCPANa, Dalapon) (CAS number 127-20-8) to suppress bacteriolysis by hen egg white lysozyme (HEWL). The system for bacteriolysis of Gram-negative bacteria Actinobacillus, Haemophilus, and Pasteurella in Tris-maleate buffer supplemented with EDTA and HEWL developed by Brondz et al. [1–4] was used to monitor bacteriolysis of Gram-negative bacteria in the Actinobacillus–Haemophilus–Pasteurella group. The halogenated acetic acid DCA is produced as a toxic artifact of the degradation of TCA and by disinfection of drinking and pool water and industrial waste. Nearly all humans consume DCA in drinking water during their lifetime;the concentration of DCA in drinking water can be higher than that associated with the upper-bound excess life-time cancer risk of 10–4 (40μg/L) [5]. Lysozyme found in tears, saliva, nasal secretions, and excretions from all mucous membranes can break down the cell walls of bacteria and destabilize bacterial membranes. Lysozyme is involved in innate (nonspecific) immunity;the innate immune system is the first line of defense against invading organisms. Actinobacillus actinomy- cetemcomitans (ATCC29522), a Gram-negative bacterium whose primary ecological niche is the respiratory tract and oral cavity, provided the peptidoglycan substrate for HEWL. The optical density (OD) of a standardized suspension of A. actinomycetemcomitans decreased from 100% (OD 0.6 at 540 nm) to 23.5% after exposure to EDTA/HEWL for 50 min. After 50 min of exposure to 10.0 mg/mL of MCA, DCA, TCA, or 2,2-DCPANa as a supplement, EDTA/HEWL-induced lysis of A. actinomycetemcomitans decreased to 66.3%, 66.8%, 65.7%, and 73.6%, respectively. The aim of the presented study was the development of a model for measuring possible immunotoxic effects of chemicals, degradation products, xenobiotics and metabolites by these chemicals on the immune system. The method used is an in vitro bacteriolysis of Gram- negative bacterium induced by HEWL, described previously [1-4]. In the present study, several halogenated acids, MCA, DCA, and TCA, and the Na salt of 2,2-DCPA, exhibited immunosuppressive activity. The ability of MCA, DCA, TCA, and 2,2-DCPANa (Dalapon) to suppress HEWL induced bacteriolysis was demonstrated in vitro. document.