A comparative study on the effect of homobrassinolide and gibberellic acid on lipid peroxidation and antioxidant status in normal and diabetic rats

Gibberellic acid targeting ZBTB16 reduces NF-κB dependent inflammatory stress in sepsis-induced neuroinflammation

OBJECTIVE

Sepsis is frequently complicated by neuroinflammation. Gibberellic acid (GA3) is recognized for its anti-inflammatory properties. In this study, our objective was to investigate whether GA3 could alleviate Nuclear factor-kappa B (NF-κB) -dependent inflammatory stress in sepsis-induced neuroinflammation.

METHODS

C57BL/6 J mice were administered 10 mg/kg lipopolysaccharide (LPS) to induce sepsis. BV2 cells were pre-incubated with GA3 and subjected lipopolysaccharide stimulation to replicate the inflammatory microglia during sepsis. Subsequently, we assessed the release of IL-6, TNF-α, and IL-1β, along with the expression of Zbtb16, NF-κB, and IκB. To investigate whether any observed anti-inflammatory effects of GA3 were mediated through a Zbtb16-dependent mechanism, Zbtb16 was silenced using siRNA.

RESULTS

GA3 improved the survival of sepsis mice and alleviated post-sepsis cognitive impairment. Additionally, GA3 attenuated microglial M1 activation (pro-inflammatory phenotype), inflammation, and neuronal damage in the brain. Moreover, GA3 inhibited the release of TNF-α, IL-6, and IL-1β in microglia stimulated with LPS. The NF-κB signaling pathway emerged as one of the key molecular pathways associated with the impact of GA3 on LPS-stimulated microglia. Lastly, GA3 upregulated Zbtb16 expression in microglia that had been downregulated by LPS. The inhibitory effects of GA3 on microglial M1 activation were partially reversed through siRNA knockdown of Zbtb16.

CONCLUSIONS

Pre-incubation of microglia with GA3 led to the upregulation of the NF-κB regulator, Zbtb16. This process counteracted LPS-induced microglial M1 activation, resulting in an anti-inflammatory effect upon subsequent LPS stimulation.

Interkingdom Hormonal Regulations between Plants and Animals Provide New Insight into Food Safety

Food safety has become an attractive topic among consumers. Raw material production for food is also a focus of social attention. As hormones are widely used in agriculture and human disease control, consumers' concerns about the safety of hormone agents have never disappeared. The present review focuses on the interkingdom regulations of exogenous animal hormones in plants and phytohormones in animals, including physiology and stress resistance. We summarize these interactions to give the public, researchers, and policymakers some guidance and suggestions. Accumulated evidence demonstrates comprehensive hormonal regulation across plants and animals. Animal hormones, interacting with phytohormones, help regulate plant development and enhance environmental resistance. Correspondingly, phytohormones may also cause damage to the reproductive and urinary systems of animals. Notably, the disease-resistant role of phytohormones is revealed against neurodegenerative diseases, cardiovascular disease, cancer, and diabetes. These resistances derive from the control for abnormal cell cycle, energy balance, and activity of enzymes. Further exploration of these cross-kingdom mechanisms would surely be of greater benefit to human health and agriculture development.

Chrysin abrogates gibberellic acid-induced testicular oxidative stress and dysfunction via the regulation of antioxidants and steroidogenesis- and apoptosis-associated genes

GA3 is widely used as a growth stimulant in agricultural regions. The long-term use of GA3 can cause organs damage. Chrysin is a flavonoid found in nature that is commonly used to treat organ toxicity. In this study, we examined the effect of chrysin on the testes function of GA3-affected rats. A total of 24 male Wistar rats were divided into 4 groups. Saline was given to the control group. The chrysin group was given orally 50 mg/kg/BW of chrysin in saline. The GA3 group received a daily oral gavage of GA3 (55 mg/kg/BW). The protective group (chrysin + GA3) was given chrysin and GA3 as those described in chrysin and GA3 groups. There were an increase in MDA levels in the serum and testicular tissue of GA3-treated group. Catalase, GSH, and SOD levels were all lowered in the GA3-treated rats. Chrysin dramatically reduced the harmful effects of GA3 by restoring reproductive hormone levels, altered sperm parameters, and antioxidant capabilities. Furthermore, GA3 reduced the quantitative expression of steroidogenesis genes StAR and 3-HSD, as well as Bcl2 genes, while it increased the apoptotic marker BAX; all were alleviated by the pre-administration of chrysin. The pre-administration of chrysin protected the GA3 group from spermatogenic vacuolation, interstitial edema, necrosis, and depletion. Chrysin inhibited oxidative stress and modulated antioxidant activity, as well as apoptosis-/anti-apoptosis-related mediators in the testes. Chrysin has the potential to repair GA3-induced testicular dysfunctions. This suggests that chrysin is preferable as a medication to mitigate GA3-induced oxidative damage in the testes. PRACTICAL APPLICATIONS: Chrysin has the potential to repair GA3-induced testicular dysfunctions. This suggests that chrysin is preferable as a medication to mitigate GA3-induced oxidative damage in the testes.

Protective effect of Pterocarpus marsupium bark extracts against cataract through the inhibition of aldose reductase activity in streptozotocin-induced diabetic male albino rats

The present study was aimed to investigate the protective effect of Pterocarpus marsupium bark extracts against cataract in streptozotocin-induced diabetic male albino rats. Aldose reductase is a key enzyme in the intracellular polyol pathway, which plays a major role in the development of diabetic cataract. Rats were divided into five groups as normal control, diabetic control, and diabetic control treated with different concentrations of Pterocarpus marsupium bark extracts. Presence of major constituents in Pterocarpus marsupium bark extract was performed by qualitative analysis. Body weight changes, blood glucose, blood insulin, and reduced glutathione (GSH) and aldose reductase mRNA and protein expression were determined. Rat body weight gain was noted following treatment with bark extracts. The blood glucose was reduced up to 36% following treatment with bark extracts. The blood insulin and tissue GSH contents were substantially increased more than 100% in diabetic rats following treatment with extracts. Aldose reductase activity was reduced up to 79.3% in diabetic rats following treatment with extracts. V_max, K_m, and K_i of aldose reductase were reduced in the lens tissue homogenate compared to the diabetic control. Aldose reductase mRNA and protein expression were reduced more than 50% following treatment with extracts. Treatment with Pterocarpus marsupium bark was able to normalize these levels. Taking all these data together, it is concluded that the use of Pterocarpus marsupium bark extracts could be the potential therapeutic approach for the reduction of aldose reductase against diabetic cataract.

Therapeutic effect of 28-homobrassinolide on leukotriene synthesis in leukemia cells

The present study was aimed to investigate the effect of 28-homobrassinolide on leukotriene synthesis in the 2H3 cells. Cell viability was determined by using sulforhodamine B (SRB) assay. Leukotriene C4 (LTC4) and Leukotriene B4 (LTB4) were determined in the cell and cell lysates. Intracellular Ca2+ was determined in the intact cells. Phospholipases A2 (PLA2) expression was determined in the cells using immunofluorescence. LTC4 and LTB4 were tremendously increased in IgE-loaded 2H3 cells. However, these levels were significantly reduced following treatment with 28-homobrassinolide. The intracellular Ca2+ level was not altered by treatment. Expression of PLA2 was significantly reduced following treatment with 28-homobrassinolide. Taking all these data together, it is suggested that the 28-homobrassinolide may be a potential therapeutic agent to inhibit leukotriene synthesis in 2H3 cells.

In vivo therapeutic potential of Inula racemosa in hepatic ischemia-reperfusion injury following orthotopic liver transplantation in male albino rats

Hepatic ischemia-reperfusion (I/R) injury mainly occurs following hepatic resection and liver transplantation and cause severe liver damage, organ injuries, and dysfunction. Pro-inflammatory cytokines that promote injury are released when kupffer cell activates after getting induced by I/R. Repercussions of oxidative stress and cardiac function against isoproterenol based myocardial infarction are caused by flavonol glycosides which are found in high concentrations in Inula racemosa (Ir).The root was deemed to have analgesic and anti-inflammatory effects, and no report has been published about the liver-protective activity against hepatic I/R. Therefore, the present study was aimed to understand the therapeutic impact of Ir in hepatic I/R injury. Male albino, Wistar strain rats were used and were grouped into four total phenolic content, free radical scavenging activity and serum enzymes were determined. Histopathological and immunohistochemical analysis were also carried out. Inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin (IL-6) and protein expression of p53, bax, and bcl-2 were determined. The administration of extracts of Ir significantly increased total phenolic and free radical scavenging activity. Altered cellular morphology, cytokines and aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) were returned to near normal level. IL-6 and TNF-α levels were reduced more than 25% following treatment. Also, the protein expression of p53, bax, and bcl-2 were also returned to near normal level. Taking all these data together, it is suggested that the extracts of Ir may be a potential therapeutic agent for providing several beneficial effects in hepatic I/R injury.

Phytoecdysteroids from Ajuga iva act as potential antidiabetic agent against alloxan-induced diabetic male albino rats

The present study investigated the protective effect of phytoecdysteroids extracted from the Ajuga iva plant on body weight changes, blood glucose, insulin total protein, blood urea nitrogen (BUN), creatinine, triglycerides (TG), cholesterol, lipid peroxidation, antioxidant enzymes, pancreatic histopathology and hexokinase-I expression in the alloxan-induced diabetic rats. Experimental diabetes was induced following 15day intraperitoneal administration of alloxan. The rats were divided into four groups. Group I served as a sham group, and group II served as the diabetic control. Group III served as a treatment for phytoecdysteroids (10mg/kg), and group IV served as a treatment for phytoecdysteroids (20mg/kg). Phytoecdysteroids restored body weight loss to its antihyperglycemic effect. Blood glucose was reduced 19.2 and 52.9% in group III and IV respectively. Blood insulin (54.9 and 105.88%) and total protein (25 and 72.2%) was increased in group III and IV respectively. BUN, creatinine, TG, cholesterol and lipid peroxidation was significantly reduced following treatment. Catalase, superoxide dismutase (SOD), and glutathione peroxidase activity were significantly increased following treatment. Islet β-cells are lost in alloxan-induced diabetic rats. Regeneration of islets and reduced atrophy of acinar cells were noted. The number of insulin-secreting cells was tremendously reduced in alloxan-induced diabetic rats. Insulin-secreting cells were increased 48 and 61% in group III and IV respectively. Hexokinase-I mRNA (28.3 & 93.5%) and protein (27.9 and 55.3%) expression were significantly increased following treatment. Taking all these data together, it is suggested that the phytoecdysteroid could be a potential therapeutic agent against experimental diabetes.

Therapeutic potential of cyanobacteria against streptozotocin-induced diabetic rats

Hypoglycemic effect of cyanobacteria has evaluated in the normal and streptozotocin-induced diabetic male albino rats as a mammalian model. Normal and streptozotocin-diabetic rats were orally administered cyanobacteria for 60 consecutive days, and their blood levels of glucose, insulin, C-peptide, lipid peroxidation, body weight and enzyme changes were determined using standard methods. Cyanobacteria administration reduced blood glucose level, and increased plasma insulin, C-peptide levels and restored the body weight. Cyanobacteria administration significantly reduced lipid peroxidation in the diabetic rats. Hexokinase enzyme activity was increased, whereas glucose-6-phosphatase enzyme activity decreased in streptozotocin-diabetic rats compared to their respective controls. Cyanobacteria administration caused significant renormalization of serum hepatic enzymes in streptozotocin-induced diabetic rats. In conclusion, cyanobacteria have a protective effect on anti-oxidant and anti-diabetic in streptozotocin-induced diabetic rats.

Induction of the inflammatory regulator A20 by gibberellic acid in airway epithelial cells

BACKGROUND AND PURPOSE

NF-κB-driven inflammation is negatively regulated by the zinc finger protein A20. Gibberellic acid (GA3 ) is a plant-derived diterpenoid with documented anti-inflammatory activity, which is reported to induce A20-like zinc finger proteins in plants. Here, we sought to investigate the anti-inflammatory effect of GA3 in airway epithelial cells and determine if the anti-inflammatory action relates to A20 induction.

EXPERIMENTAL APPROACH

Primary nasal epithelial cells and a human bronchial epithelial cell line (16HBE14o-) were used. Cells were pre-incubated with GA3 , stimulated with Pseudomonas aeruginosa LPS; IL-6 and IL-8 release, A20, NF-κB and IκBα expression were then evaluated. To determine if any observed anti-inflammatory effect occurred via an A20-dependent mechanism, A20 was silenced using siRNA.

KEY RESULTS

Cells pre-incubated with GA3 had significantly increased levels of A20 mRNA (4 h) and protein (24 h), resulting in a significant reduction in IL-6 and IL-8 release. This effect was mediated via reduced IκBα degradation and reduced NF-κB (p65) expression. Furthermore, the anti-inflammatory action of GA3 was abolished in A20-silenced cells.

CONCLUSIONS AND IMPLICATIONS

We showed that A20 induction by GA3 attenuates inflammation in airway epithelial cells, at least in part through its effect on NF-κB and IκBα. GA3 or gibberellin-derived derivatives could potentially be developed into anti-inflammatory drugs for the treatment of chronic inflammatory diseases associated with A20 dysfunction.

Steroid plant hormones: effects outside plant kingdom

Brassinosteroids (BS) are the first group of steroid-hormonal compounds isolated from and acting in plants. Among numerous physiological effects of BS growth stimulation and adaptogenic activities are especially remarkable. In this review, we provide evidence that BS possess similar types of activity also beyond plant kingdom at concentrations comparable with those for plants. This finding allows looking at steroids from a new point of view: how common are the mechanisms of steroid bioregulation in different types of organisms from protozoa to higher animals.

A phytooxysterol, 28-homobrassinolide modulates rat testicular steroidogenesis in normal and diabetic rats

Steroidogenesis in testicular cells depends upon the availability of cholesterol within testicular mitochondria besides the activities of 3β-hydroxysteroid dehydrogenase (3β-HSD, 17β-hydroxysteroid dehydrogenase [17b-HSD]), and the tissue levels of steroidogenic acute regulatory protein (StAR), androgen-binding protein (ABP), and testosterone (T). Cellular cholesterol biosynthesis is regulated by endogenous oxycholesterols acting through nuclear hormone receptors. Plant oxysterols, such as 28-homobrassinolide (28-HB), available to human through diet, was shown to exhibit antihyperglycemic effect in diabetic male rat. Its role in rat testicular steroidogenesis and lipid peroxidation (LPO) was therefore assessed using normal and streptozotocin-induced diabetic male rats. Administration of 28-HB (333 µg/kg body weight) by oral gavage for 15 consecutive days to experimental rats diminished LPO, increased antioxidant enzyme, 3β-HSD and 17β-HSD activities, and elevated StAR and ABP expression and T level in rat testis. We report that 28-HB induced steroidogenesis in normal and diabetic rat testis.

Brassinosteroids and analogs as neuroprotectors: synthesis and structure-activity relationships

We have demonstrated previously that the brassinosteroid (BR) 24-epibrassinolide exerts neuroprotective effects deriving from its antioxidative properties. In this study, we synthesized 2 natural BRs and 5 synthetic analogs and analyzed their neuroprotective actions in neuronal PC12 cells, against 1-methyl-4-phenylpyridinium (MPP(+)), a neurotoxin known to induce oxidative stress and degenerescence of dopaminergic neurons characteristic of Parkinsonian brains. We also tested the neuroprotective potential of 2 commercially available BRs. Our results disclosed that 6 of the 9 BRs and analogs tested protected neuronal PC12 cells against MPP(+) toxicity. In addition, our structure-activity study suggests that the steroid B-ring and lateral chain play an important role for their neuroprotective action.

Induction of hexokinase I expression in normal and diabetic rats by a brassinosteroid isoform

This study aimed to investigate the effect of the plant growth regulator 28-homobrassinolide (HB) on the hexokinase I (HK I) enzyme gene expression in the tissues of normal and streptozotocin-induced diabetic rats. Normal and diabetic rats were administered 50 microg of HB for 15 consecutive days. The tissues level of HK I mRNA expression was quantitated by PCR and densitometry analysis, HK I protein expression was quantitated by Western blot and densitometry analysis, localization of HK I was done by immunohistochemistry and HK enzyme activity was determined by coupled enzyme assay. Subchronic treatment of rats with HB enhanced HK I enzyme expression in diabetic rat compared to the control rat. From these experimental evidences, we came to the conclusion that HK I played a vital role in the regulation of blood sugar in streptozotocin-induced diabetic rats. A direct role for hexokinase enzyme activity in the control of diabetes is presented.