Apoptotic inducement of neuronal cells by codeine: possible role of disrupted redox state and caspase 3 signaling

Antitussive drug dextromethorphan induces developmental impairment in zebrafish

Dextromethorphan (DXM) is a common ingredient in cough and cold remedies. Despite its widespread presence in aquatic environments, the impact of DXM on fish remains largely unknown. This study evaluated the developmental impairment of zebrafish embryos exposed to DXM from 2 hours post-fertilization (hpf) to 14 days post-fertilization (dpf) at five different exposure concentrations: 0.06, 0.61, 8.12, 76.3, and 827 μg/L. Results indicated a concentration-dependent increase in bioconcentration of DXM at 7 dpf and 14 dpf. The LC50 at 14 dpf was 93.3 μg/L, demonstrating DXM has a high toxicity to zebrafish larvae. Additionally, DXM reduced body length and heart rate, and elevated malformation in a dose-dependent manner in larvae at 72 hpf, 7 dpf and 14 dpf. Biochemical analysis (DNA conformations and 8-hydroxy-2deoxyguanosine level) and transcriptomic analysis (DNA damage and cell cycle) indicated that DXM triggered DNA damage in larvae. Concurrently, DXM triggered DNA damage response (e.g., cell cycle arrest, DNA repair failure, and cell apoptosis) in larvae at 7 dpf and 14 dpf. These results help explain DXM caused severe developmental impairment via DNA damage-related pathways in zebrafish larvae, highlighting the importance of focusing on ecological and public health risks of DXM in natural environment.

L-Arginine abrogates maternal and pre-pubertal codeine exposure-induced impaired spermatogenesis and sperm quality by modulating the levels of mRNA encoding spermatogenic genes

INTRODUCTION

Although, codeine has been demonstrated to lower sperm quality; the effects of maternal and prepubertal codeine exposure on male offspring is yet to be reported. In addition, the effect of arginine on codeine-induced decline in sperm quality has not been explored. This study investigated the impact of maternal and prepubertal codeine exposure on spermatogenesis and sperm quality in F1 male Wistar rats to study the effect that codeine may have during recreational use in humans. Also, the effect of arginine supplementation on codeine-induced alteration in spermatogenesis and sperm quality was evaluated.

METHODS

Female rats were treated with either 0.5 ml distilled water or codeine orally for eight weeks, and then mated with male rats (female:male, 2:1). The F1 male offsprings of both cohorts were weaned at 3 weeks old and administered distilled water, codeine, arginine, or codeine with arginine orally for eight weeks.

RESULTS

Prepubertal codeine exposure in rats whose dams (female parents) were exposed to codeine delayed puberty and reduced the weight at puberty. Prepubertal codeine exposure exacerbated maternal codeine exposure-induced reduced total and daily spermatid production, sperm count, sperm motility, and normal sperm form, as well as impaired sperm plasma membrane integrity and increased not intact acrosome and damaged sperm DNA integrity. These perturbations were accompanied by a decrease in mRNA levels encoding spermatogenic genes, testicular testosterone and androgen receptor (AR) concentrations, and upregulation of sperm 8-hydroxydeoxyguanosine (8OHdG). Prepubertal arginine supplementation mitigated codeine-induced alterations.

DISCUSSION

This study provides novel experimental evidence that maternal and prepubertal codeine exposure reprogramed spermatogenesis and sperm quality of male FI generation by decreasing mRNA levels encoding spermatogenic genes and AR via oxidative stress-mediated signaling, which was abrogated by prepubertal arginine supplementation.

Proton Pump Dysfunction and Upregulation of Caspase-3 Activity via Oxidative-Sensitive Signaling Mediate Rohypnol-Induced Testicular Toxicity

Rohypnol is a benzodiazepine that is used for its anxiolytic, anticonvulsant, muscle relaxant, and hypnotic properties, but commonly abused. It has been reported to induce sexual dysfunction; however, its effect on testicular integrity and sperm quality is yet to be documented. This study evaluated the impact of Rohypnol on testicular integrity, circulatory testosterone, spermatogenesis, and sperm quality. The likely role of oxidative stress-dependent pathway as well as testicular proton pumps and caspase-3 activity in Rohypnol-induced modulation of male reproductive function was explored. In this study, adult male rats were randomized into six groups of six rats each: the control received 1 ml of distilled water as vehicle, while the low- and high-dose Rohypnol-treated groups received 2 mg/kg and 4 mg/kg of Rohypnol for four weeks. The control-, low-, and high-dose recovery groups received 2 mg/kg and 4 mg/kg of Rohypnol for four weeks, respectively, which was followed by a 4-week drug-free recovery period. Rohypnol treatments led to impaired steroidogenesis and spermatogenesis and low sperm quality. This was accompanied by a rise in the markers of testicular injury, oxidative stress, inflammation, and apoptosis. Also, the activities of testicular enzymatic antioxidants and proton pumps were significantly reduced. Although the impacts of low-dose Rohypnol treatment were partially reversible, those of the high-dose Rohypnol treatment were not. Histopathological findings on the testicular tissues were in tandem with the biochemical alterations. Thus, it is safe to infer that Rohypnol induces testicular damage by the suppression of Na+/K+-ATPase and Ca2+-ATPase and the activation of caspase-3 through an oxidative-sensitive signaling pathway.

Mu opioid receptor-mediated release of endolysosome iron increases levels of mitochondrial iron, reactive oxygen species, and cell death

Objectives

Opioids including morphine and DAMGO activate mu-opioid receptors (MOR), increase intracellular reactive oxygen species (ROS) levels, and induce cell death. Ferrous iron (Fe2+) through Fenton-like chemistry increases ROS levels and endolysosomes are "master regulators of iron metabolism" and contain readily-releasable Fe2+ stores. However, mechanisms underlying opioid-induced changes in endolysosome iron homeostasis and downstream-signaling events remain unclear.

Methods

We used SH-SY5Y neuroblastoma cells, flow cytometry, and confocal microscopy to measure Fe2+ and ROS levels and cell death.

Results

Morphine and DAMGO de-acidified endolysosomes, decreased endolysosome Fe2+ levels, increased cytosol and mitochondria Fe2+ and ROS levels, depolarized mitochondrial membrane potential, and induced cell death; effects blocked by the nonselective MOR antagonist naloxone and the selective MOR antagonist β-funaltrexamine (β-FNA). Deferoxamine, an endolysosome-iron chelator, inhibited opioid agonist-induced increases in cytosolic and mitochondrial Fe2+ and ROS. Opioid-induced efflux of endolysosome Fe2+ and subsequent Fe2+ accumulation in mitochondria were blocked by the endolysosome-resident two-pore channel inhibitor NED-19 and the mitochondrial permeability transition pore inhibitor TRO.

Conclusions

Opioid agonist-induced increases in cytosolic and mitochondrial Fe2+ and ROS as well as cell death appear downstream of endolysosome de-acidification and Fe2+ efflux from the endolysosome iron pool that is sufficient to affect other organelles.

L-Arginine reverses maternal and pre-pubertal codeine exposure-induced sexual dysfunction via upregulation of androgen receptor gene and NO/cGMP signaling

BACKGROUND

Although codeine has been reported to enhance sexual activity by improving penile reflexes, it has been shown to impair fertility indices. Also, codeine impairs ovarian steroidogenesis and folliculogenesis. Nonetheless, whether or not codeine exerts an epigenetic effect remains unclear. On the other hand, arginine has been speculated to enhance penile reflexes by upregulating NO/cGMP Signaling.

AIM

The study evaluated the effect of maternal codeine exposure and prepubertal codeine and arginine treatments on F1 male sexual function and fertility indices, as well as the outcome of F2 progenies. In addition, the epigenetic programming mechanism was also explored.

METHODS

Forty three-week-old female rats were randomized into two groups (n = 20 rats/group); the control that received 0.5 ml of distilled water and the codeine-treated that received 5 mg/kg of codeine via gavage for eight weeks. Afterward, the female rats were paired for mating with sexually mature male rats. Rats were maintained on their pre-pregnancy treatments throughout pregnancy and lactation. FI progenies from each cohort (control and codeine-treated cohorts) were weaned at three weeks and randomized into four groups; the control, codeine-treated, L-arginine-treated (300mg/kg), and codeine + L-arginine-treated (n = 10 rats/group). Administration commenced a week post-weaning and lasted for eight weeks via gavage.

KEY FINDINGS

Maternal codeine exposure did not alter body weight, but significantly reduced anogenital distance and anogenital index of F1 male offspring. Also, maternal codeine delayed preputial membrane separation, impaired male sexual competence, and penile reflexes of F1 male offsprings. These were associated with reduced dopamine, gonadotropins, and testosterone levels as well as suppressed expression of androgen receptor mRNA. In addition, maternal codeine downregulated NO/cGMP signaling, impaired fertility indices, and reduced the litter size, weight, and survival of F2 progenies. These alterations were observed to be aggravated by prepubertal codeine exposure but improved by prepubertal arginine treatment.

SIGNIFICANCE

In conclusion, codeine programmed sexual dysfunction by suppressing the levels of dopamine and testosterone, as well as repressing the expression of androgen receptor mRNA. In addition, codeine-induced epigenetic reprogramming was expressed in the F2 offsprings as reduced litter size and weight, and survival rate. Notably, these observations were worsened by prepubertal codeine exposure, but dampened by prepubertal arginine treatment.

Codeine alters female reproductive function by targeting ovarian steroidogenesis and folliculogenesis via the induction of oxidative stress, inflammation, and apoptosis

The rise in the abuse of codeine raises concerns about its impact on the health of users, and little has appeared on its effect on the female reproductive function. Therefore, this study evaluated the impact of codeine on female reproductive function. We administered codeine at low (2 mg/kg) and high (5 mg/kg) doses to female animals prior to mating for 8 weeks. In comparison with a vehicle-treated group, we then assessed the impact of codeine on body weight gain and ovarian weight, female sexual behaviour, ovarian steroidogenesis, and folliculogenesis. The role of oxidative stress, inflammation, and apoptosis were also evaluated. Codeine at either dose elicited a profound deficit in the absolute and relative ovarian weight, indicative of ovarian toxicity. Also, codeine induced female sexual dysfunction, and suppressed ovarian steroidogenesis and folliculogenesis, with degeneration of the ovarian cytoarchitecture and follicles. The effects of codeine were associated with a rise in ovarian hydroxyl radical generation and oxidative stress, evident by an increase in ovarian malondialdehyde, a reduction in reduced glutathione, and a decline in the activities of ovarian enzymatic antioxidants. In addition, codeine triggered an increase in the ovarian concentration of inflammatory cytokines, TNF-α and IL-1β, and myeloperoxidase activity. Furthermore, codeine caused an increase in 8-hydroxydeoxyguanosine (8OHdG), ovarian DNA fragmentation, and caspase-3 activity, suggestive of genotoxicity and apoptosis respectively. The current study provides some of the first evidence for the adverse effects of prolong codeine use on female sexual function, ovarian steroidogenesis, and folliculogenesis. It also emphasizes the reproductive health consequences of drug abuse.