Influence of anti- and prooxidants on rhizogenesis from hypocotyls of Mesembryanthemum crystallinum L. cultured in vitro

The enrichment with antioxidants (glutathione or ascorbate) or prooxidants (alloxan, methylviologen, hydrogen peroxide) of root inducing medium significantly decreased rhizogenesis frequency (alloxan, hydrogen peroxide) or inhibited roots regeneration (ascorbate, methylviologen) during the in vitro culture of Mesembryanthemum crystallinum L. hypocotyls. The adventitious roots morphology, root hairs length and density, was also influenced. Changes in the rhizogenesis course were related to the differences in hydrogen peroxide concentration during following days of culture between explants exhibiting morphogenic potential and those without the ability to form adventitious roots. In explants with morphogenic potential, rhizogenesis induction was always accompanied by a high level of hydrogen peroxide followed by the decrease in H_{2}O_{2} content in following days. In contrast, in the explants without regeneration potential, the level of hydrogen peroxide was increasing during the culture period. Activity patterns of superoxide dismutase (SOD) and guaiacol peroxidase (POX) in the following days of culture were similar in the explants exhibiting regeneration potential cultured on different media. Total activity of SOD decreased during initial days of culture and then increased due to the activation of additional SOD isoform described as MnSODII. The activity of POX was low during the rhizogenesis induction, and then increased during following days of culture; the increase was correlated with the decrease in hydrogen peroxide content. In the explants without the ability to regenerate roots, the total activity of SOD was low throughout the whole culture period, whereas the POX activity was significantly higher than in hypocotyls with regeneration potential. It might be concluded that the increase in hydrogen peroxide during initial stages of rhizogenesis and the induction of MnSODII are prerequisites for adventitious roots formation from hypocotyls of M. crystallinum, independently in the presence of anti- or prooxidant in the culture medium

Efficacy of comprehensive dental treatment for lichenoid reactions of the mucoparodontal complex: A single-center pilot cohort study

Background. Lichenoid reactions of the oral mucosa are currently recognized as a serious issue for dentists of various specialties, since their knowledge and competence in the diagnosis and pathogenetic treatment of lichenoid lesions of the oral cavity are yet to be improved. Following the data on high oncogenic potential in some forms of lichenoid reactions of oral cavity mucous membranes, the issue should be given serious considerations, and dentists should keep oncology-related suspicion when receiving these patients.Objective. To evaluate the efficacy of comprehensive dental treatment for lichenoid reactions of the mucoparodontal complex.Methods. A single-center pilot cohort study was conducted to evaluate the efficacy of the comprehensive treatment (combination of pharmacotherapy and physiotherapy) of patients with lichenoid reactions of the oral mucosa. The observation group consisted of 49 patients (15 males, 34 females) aged 58.92 ± 0.82 years with verified diagnoses of oral mucosa lichenoid reactions. The suggested treatment included pharmacotherapy (highly-potent topical steroids, calcineurin inhibitors) and physiotherapy in the form of low level laser therapy (635 nm, 10 W) provided via Matrix laser (Matrix, Russia). Treatment efficacy was assessed by the total scale of treatment efficacy, registering indicators of the area of focal lesions and the severity of pain syndrome, as well as by changes in dental quality of life indicators according to OHIP-49-RU (Oral Health Impact Profile) in the Russian version. Statistical processing of the data involved Student’s t-test and Wilcoxon t-test. Differences were considered significant at p ≤ 0.05. Data statistical analysis was performed using SPSS 13.0 (SPSS Inc., USA).Results. During the follow-up period, the indicators of the total scale of treatment efficacy decreased significantly (p < 0.001) in 100% of patients and amounted (as medians and quartiles): 6.0 (4.0–7.0) points before treatment and 1.0 (1.0–2.0) points after treatment to be objectified by a significant reduction in the area of focal lesions (by 63.2%, p < 0.001) and in pain syndrome (spontaneous pain from 2.0 (1.5–3.0) points before treatment to 0.0 (0.0–1.0) points after treatment; induced pain from 3.0 (2.0–3.0) points to 1.0 (0.0–1.0) points). Along with the clinical improvement, the scores in dental quality of life improved from 83.11 ± 2.58 to 39.94 ± 0.86 points, according to OHIP-49 RU (Oral Health Impact Profile).Conclusion. Early detection and differentiation of lichenoid reactions in oral mucous membranes ensure timely treatment using the developed protocol of comprehensive treatment (combination of pharmacotherapy and physiotherapy). The efficacy of the protocol was confirmed clinically and justified in relation to quality of life

The localization of NADPH oxidase and reactive oxygen species in in vitro-cultured Mesembryanthemum crystallinum L. hypocotyls discloses their differing roles in rhizogenesis

This work demonstrated how reactive oxygen species (ROS) are involved in the regulation of rhizogenesis from hypocotyls of Mesembryanthemum crystallinum L. cultured on a medium containing 1-naphthaleneacetic acid (NAA). The increase of NADPH oxidase activity was correlated with an increase of hydrogen peroxide (H2O2) content and induction of mitotic activity in vascular cylinder cells, leading to root formation from cultured hypocotyls. Diphenylene iodonium (DPI), an inhibitor of NADPH oxidase, inhibited H2O2 production and blocked rhizogenesis. Ultrastructural studies revealed differences in H2O2 localization between the vascular cylinder cells and cortex parenchyma cells of cultured explants. We suggest that NADPH oxidase is responsible for H2O2 level regulation in vascular cylinder cells, while peroxidase (POD) participates in H2O2 level regulation in cortex cells. Blue formazan (NBT) precipitates indicating superoxide radical (O2 •−) accumulation were localized within the vascular cylinder cells during the early stages of rhizogenesis and at the tip of root primordia, as well as in the distal and middle parts of newly formed organs. 3,3′-diaminobenzidine (DAB) staining of H2O2 was more intense in vascular bundle cells and in cortex cells. In newly formed roots, H2O2 was localized in vascular tissue. Adding DPI to the medium led to a decrease in the intensity of NBT and DAB staining in cultured explants. Accumulation of O2 •− was then limited to epidermis cells, while H2O2 was accumulated only in vascular tissue. These results indicate that O2 •− is engaged in processes of rhizogenesis induction involving division of competent cells, while H2O2 is engaged in developmental processes mainly involving cell growth