Pretreatment with valproic acid, a histone deacetylase inhibitor, enhances the sensitivity of the peripheral blood micronucleus assay in rodents

A systematic overview of the spermatotoxic and genotoxic effects of methotrexate, ganciclovir and mycophenolate mofetil

INTRODUCTION

Immunosuppressant drugs are increasingly being used in the reproductive years. Theoretically, such medications could affect fetal health either through changes in the sperm DNA or through fetal exposure caused by a presence in the seminal fluid. This systematic overview summarizes existing literature on the spermatotoxic and genotoxic potentials of methotrexate (MTX), a drug widely used to treat rheumatic and dermatologic diseases, and mycophenolate mofetil (MMF), which alone or supplemented with ganciclovir (GCV) may be crucial for the survival of organ transplants.

MATERIAL AND METHODS

The systematic overview was performed in accordance with the PRISMA guidelines: A systematic literature search of the MEDLINE and Embase databases was done using a combination of relevant terms to search for studies on spermatotoxic or genotoxic changes related to treatment with MTX, GCV or MMF. The search was restricted to English language literature, and to in vivo animal studies (mammalian species) and clinical human studies.

RESULTS

A total of 102 studies were identified, hereof 25 human and 77 animal studies. For MTX, human studies of immunosuppressive dosages show transient effect on sperm quality parameters, which return to reference values within 3 months. No human studies have investigated the sperm DNA damaging effect of MTX, but in other organs the genotoxic effects of immunosuppressive doses of MTX are fluctuating. In animals, immunosuppressive and cytotoxic doses of MTX adversely affect sperm quality parameters and show widespread genotoxic damages in various organs. Cytotoxic doses transiently change the DNA material in all cell stages of spermatogenesis in rodents. For GCV and MMF, data are limited and the results are indeterminate, for which reason spermatotoxic and genotoxic potentials cannot be excluded.

CONCLUSIONS

Data from human and animal studies indicate transient spermatotoxic and genotoxic potentials of immunosuppressive and cytotoxic doses of MTX. There are a limited number of studies investigating GCV and MMF.

Nicotinamide attenuates cyclophosphamide-induced hepatotoxicity in SD rats by reducing oxidative stress and apoptosis

Cyclophosphamide (CP) is a widely used anticancer and immunosuppressant drug. Nevertheless, clinical utilization of CP is limited due to considerable adverse effects and toxicities. Nicotinamide (NMD) is a micronutrient and the effect of NMD against CP-induced hepatotoxicity is yet unexplored. The present study was designed to evaluate the chemoprotective effect of NMD against CP-induced hepatic injury in Sprague-Dawley rats. Hepatotoxicity was induced by the administration of CP (30 mg/kg/day) for 10 consecutive days by intraperitoneal injection. The chemoprotective effect of NMD treatment (200 mg/kg) against CP-induced hepatotoxicity was evaluated by the oxidative stress, liver function, histopathological changes, and DNA damage. NMD cotreatment significantly reduced CP-induced oxidative stress, histological changes, and apoptosis in the liver. The present study demonstrated that NMD treatment ameliorated CP-induced hepatic damage by improving the antioxidant system and reducing DNA damage. The present findings revealed that NMD supplementation might be useful to reduce CP-associated hepatotoxicity, and thereby can increase the therapeutic utility of CP.

α-Lipoic acid attenuates transplacental nicotine-induced germ cell and oxidative DNA damage in adult mice

BACKGROUND

Smoking during pregnancy is associated with numerous fetal and developmental complications and reproductive dysfunctions in the offspring. Nicotine is one of the key chemicals of tobacco responsible for addiction. The present study was aimed to investigate the protective role of α-lipoic acid (ALA) during the transplacental nicotine-induced germ cell and DNA damage in the offspring of Swiss mice.

METHODS

Pregnant mice were treated with nicotine (20 mg/kg/day) in drinking water from 10 to 20 days of gestation period, and ALA (120 mg/kg/day) was administered orally for the same period. Endpoint of evaluation includes general observations at delivery and throughout the study, litter weight and size, sperm count and sperm head morphology, while structural damages and protein expression were assessed by histology and immunohistochemistry, respectively.

RESULTS

Maternal nicotine exposure led to decreased growth rate, litter and testicular weight, testosterone level, 3β-HSD expression and sperm count as well as increased sperm head abnormalities, micronucleus frequency and 8-oxo-dG positive cells, and the effects have been restored by ALA supplementation.

CONCLUSIONS

The present study clearly demonstrated that ALA ameliorates nicotine-associated oxidative stress, DNA damage and testicular toxicity in the offspring by improving steroidogenesis, spermatogenesis and sperm count.

Sodium Butyrate Ameliorates L-Arginine-Induced Pancreatitis and Associated Fibrosis in Wistar Rat: Role of Inflammation and Nitrosative Stress

Several reports indicated that histone deacetylases (HDACs) play a crucial role in inflammation and fibrogenesis. Sodium butyrate (SB) is a short-chain fatty acid having HDAC inhibition potential. The present study aimed to evaluate the protective effect of SB against L-arginine (L-Arg)-induced pancreatic fibrosis in Wistar rats. Pancreatic fibrosis was induced by twice intraperitoneal (i.p.) injections of 20% L-Arg (250 mg/100 g) at 2-h interval on day 1, 4, 7, and 10, whereas SB (800 mg/kg/day) was administrated for 10 days. At the end of the study, biochemical estimations, histological alterations, DNA damage, and the expression of various proteins were evaluated. Posttreatment of SB decreased L-Arg-induced oxidative and nitrosative stress, DNA damage, histological alterations, and fibrosis. Interestingly, posttreatment of SB significantly decreased the expression of α-smooth muscle actin, interleukin-1β, inducible nitric oxide synthase, and 3-nitrotyrosine. The present study demonstrated that posttreatment of SB alleviates L-Arg-induced pancreatic damage and fibrosis in rat.

Sodium valproate ameliorates diabetes-induced fibrosis and renal damage by the inhibition of histone deacetylases in diabetic rat

Recent reports emphasize the contribution of histone deacetylases (HDACs) in the pathogenesis of diabetic renal injury and fibrosis. Valproic acid (VPA) is a first-line drug used for the treatment of epilepsy and migraine as well as established as a HDAC inhibitor. The present study was aimed to evaluate the anti-fibrotic and renoprotective effects of VPA in diabetic nephropathy (DN). Diabetes was induced by single injection of STZ (50mg/kg), whereas VPA at the doses of 150 and 300mg/kg/day was administered for 8 consecutive weeks by oral route in Sprague Dawley rats. The renal injuries and fibrosis were assessed by histology, fibrosis specific staining and fibroblast activation by a transmission electron microscope, while expression of proteins of interest was evaluated by western blotting and immunohistochemistry. VPA treatment ameliorated the histological alterations as well as fibrosis, and decreased the expression of TGF-β1, CTGF, α-SMA, fibronectin, collagen I, COX-2, ICAM-1 and HDAC4/5/7. Further, VPA treatment significantly increased histone H3 acetylation and MMP-2 expression. The present study clearly established that VPA treatment ameliorates the renal injury and fibrosis in diabetic kidney by preventing the myofibroblast activation and fibrogenesis by HDAC inhibition and associated mechanisms, thereby improving the profibrotic and anti-fibrotic protein balance.

Valproate ameliorates thioacetamide-induced fibrosis by hepatic stellate cell inactivation

Valproic acid (VPA) has been reported as inhibitor of histone deacetylases (HDACs). Several reports indicated that HDACs play a crucial role in the pathogenesis of fibrosis and hepatic stellate cell (HSC) activation. The present study was aimed to evaluate the anti-fibrotic effect of VPA against thioacetamide (TAA)-induced hepatic fibrosis and activation of the HSC in rat. VPA and TAA were administrated intraperitoneally at the dose of 400 and 200 mg/kg each at 2 days interval, respectively for a period of 6 weeks. Administration of TAA significantly increased the absolute and relative liver weight, aspartate aminotransferase and alanine aminotransferase levels, which were significantly decreased by VPA treatment as compared to TAA control. VPA treatment prevents the TAA-induced activation of HSC and decreases collagen deposition and infiltration of inflammatory cells as revealed by Sirius red and H&E staining. Interestingly, VPA co-treatment led to significantly increase the DNA damage and apoptosis in the activated HSC as compared to TAA control. Further, TAA decreased the expression of matrix metalloproteinase-2 (MMP-2), while VPA co-treatment significantly increased the expression of MMP-2 as compared to respective control. The present study clearly demonstrated that VPA treatment significantly alleviates TAA-induced activation of HSC and subsequent hepatic fibrosis.

Epigenetic influences in the aetiology of cancers arising from breast and prostate: a hypothesised transgenerational evolution in chromatin accessibility

Epidemiological studies have consistently supported the notion that environmental and/or dietary factors play a central role in the aetiology of cancers of the breast and prostate. However, for more than five decades investigators have failed to identify a single cause-and-effect factor, which could be implicated; identification of a causative entity would allow the implementation of an intervention strategy in at-risk populations. This suggests a more complex pathoaetiology for these cancer sites, compared to others. When one examines the increases or decreases in incidence of specific cancers amongst migrant populations, it is notable that disease arising in colon or stomach requires one or at most two generations to exhibit a change in incidence to match that of high-incidence regions, whereas for breast or prostate cancer, at least three generations are required. This generational threshold could suggest a requirement for nonmutation-driven epigenetic alterations in the F0/F1 generations (parental/offspring adopting a more westernized lifestyle), which then predisposes the inherited genome of subsequent generations to mutagenic/genotoxic alterations leading to the development of sporadic cancer in these target sites. As such, individual susceptibility to carcinogen insult would not be based per se on polymorphisms in activating/detoxifying/repair enzymes, but on elevated accessibility of crucial target genes (e.g., oncogenes, tumour suppressor genes) or hotspots therein to mutation events. This could be termed a genomic susceptibility organizational structure (SOS). Several exposures including alcohol and heavy metals are epigens (i.e., modifiers of the epigenome), whereas others are mutagenic/genotoxic, for example, heterocyclic aromatic amines; humans are continuously and variously exposed to mixtures of these agents. Within such a transgenerational multistage model of cancer development, determining the interaction between epigenetic modification to generate a genomic SOS and genotoxic insult will facilitate a new level of understanding in the aetiology of cancer.