The Influence of Paracetamol on the Penetration of Sorafenib and Sorafenib N-Oxide Through the Blood-Brain Barrier in Rats

Protective and therapeutic effects of okra seed in acute nontraumatic brain injury

AIM

The purpose of this study was to examine the protective and therapeutic effects of okra (Abelmoschus esculentus [AE]) seed extract, with its known antioxidant, immunomodulatory, and anti-inflammatory properties, in an acetaminophen (paracetamol, N-acetyl- para-aminophenol)-induced model of hepatotoxicity and subsequent acute non-traumatic brain damage.

MATERIAL AND METHOD

Forty male Wistar rats were randomly divided into five equal groups, control, paracetamol (P), okra seed extract (AE), okra seed extract + paracetamol (P + AE), and okra seed extract + paracetamol + N-acetyl cysteine (NAC) (P + AE + N). AE was administered by oral gavage through a gastric tube at 600 mg/kg/day for seven days. On the eighth day of the procedure, a single 1 g/kg dose of paracetamol and 300 mg/kg NAC were injected via the intraperitoneal route 1.5 h after AE administration. Rat tissue specimens were subsequently subjected to biochemical and histopathological analyses. Levels of markers such as S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), and matrix membrane metalloproteinase-9 (MMP-9) were investigated from rat serum specimens. Malondialdehyde (MDA) and superoxide dismutase (SOD) were also measured to determine oxidant-antioxidant status.

RESULTS

S100B, NSE, MMP-9, MDA levels, and SOD enzyme activities were examined using biochemical methods. MDA levels were significantly lower in the P + AE group and MMP-9 levels in the AE, P + AE, and P + AE + N groups compared to the P group. Histopathological examination results supported the biochemical findings.

CONCLUSION

Okra seed extract exhibits a protective and therapeutic effect against non-traumatic brain damage resulting from acute paracetamol intoxication. We think that this benefit of AE derives from its antioxidant property.

Effects of Voluntary Wheel Running Exercise on Chemotherapy-Impaired Cognitive and Motor Performance in Mice

Chemotherapy-induced cognitive impairment (chemobrain) and muscle wasting (cachexia) are persisting side effects which adversely affect the quality of life of cancer survivors. We therefore investigated the efficacy of physical exercise as a non-pharmacological intervention to reverse the adverse effects of chemotherapy. We examined whether physical exercise in terms of voluntary wheel running could prevent chemotherapy-induced cognitive and motor impairments in mice treated with the multi-kinase inhibitor sorafenib. Adult male BALB/c mice were subdivided into runner and non-runner groups and orally administered with sorafenib (60 mg/kg) or vehicle continuously for four weeks. Mice could freely access the running wheel anytime during sorafenib or vehicle treatment. We found that sorafenib treatment reduced body weight gain (% of change, vehicle: 3.28 ± 3.29, sorafenib: -9.24 ± 1.52, p = 0.0004), impaired hippocampal-dependent spatial memory in the Y maze (exploration index, vehicle: 35.57 ± 11.38%, sorafenib: -29.62 ± 7.90%, p < 0.0001), increased anhedonia-like behaviour in the sucrose preference test (sucrose preference, vehicle: 66.57 ± 3.52%, sorafenib: 44.54 ± 4.25%, p = 0.0005) and impaired motor skill acquisition in rotarod test (latency to fall on day 1: 37.87 ± 8.05 and day 2: 37.22 ± 12.26 s, p > 0.05) but did not induce muscle wasting or reduce grip strength. Concomitant voluntary running reduced anhedonia-like behaviour (sucrose preference, sedentary: 44.54 ± 4.25%, runners: 59.33 ± 4.02%, p = 0.0357), restored impairment in motor skill acquisition (latency to fall on day 1: 50.85 ± 15.45 and day 2: 168.50 ± 37.08 s, p = 0.0004), but failed to rescue spatial memory deficit. Immunostaining results revealed that sorafenib treatment did not affect the number of proliferating cells and immature neurons in the hippocampal dentate gyrus (DG), whereas running significantly increased cell proliferation in both vehicle- (total Ki-67⁺ cells, sedentary: 16,687.34 ± 72.63, exercise: 3320.03 ± 182.57, p < 0.0001) and sorafenib-treated mice (Ki-67⁺ cells in the ventral DG, sedentary: 688.82.34 ± 38.16, exercise: 979.53 ± 73.88, p < 0.0400). Our results suggest that spatial memory impairment and anhedonia-like behaviour precede the presence of muscle wasting, and these behavioural deficits are independent of the changes in adult hippocampal neurogenesis. Running effectively prevents body weight loss, improves motor skill acquisition and reduces anhedonia-like behaviour associated with increased proliferating cells and immature neurons in DG. Taken together, they support physical exercise rehabilitation as an effective strategy to prevent chemotherapy side effects in terms of mood dysregulation and motor deficit.

Comparative Pharmacokinetics and Tissue Distribution of M10 and Its Metabolite Myricetin in Normal and Dextran-Sodium-Sulfate-Induced Colitis Mice

M10, a novel myricetin derivative, is an anti-inflammatory agent designed for treatment of colitis. Here, we aim to investigate its pharmacokinetic behavior and tissue distribution in a mouse model with colitis. Pharmacokinetics and tissue distribution of M10 and its metabolite myricetin were compared in normal mice and in dextran-sodium-sulfate (DSS)-induced colitis mice. The role of fecal microbiota was also analyzed during metabolism of M10 in vitro. After oral administration, M10 was very low in the plasma of both normal and diseased mice. However, both M10 and myricetin were mainly distributed in the gastrointestinal tract, including the stomach, colon and small intestine, in physiological and pathological conditions. Significantly, M10 and myricetin were found in higher levels in gastrointestinal tracts with inflamed tissues than in normal tissues of mice. An in vitro assay revealed that 80% of M10 was metabolized to myricetin via fecal microbiota. After oral administration, M10 was not absorbed into circulation but mainly distributed in the inflamed submucosal tissues of colitic mice, where it was metabolized into myricetin to prevent colitis development.

High-Dose Acetaminophen Alters the Integrity of the Blood-Brain Barrier and Leads to Increased CNS Uptake of Codeine in Rats

The consumption of acetaminophen (APAP) can induce neurological changes in human subjects; however, effects of APAP on blood-brain barrier (BBB) integrity are unknown. BBB changes by APAP can have profound consequences for brain delivery of co-administered drugs. To study APAP effects, female Sprague-Dawley rats (12-16 weeks old) were administered vehicle (i.e., 100% dimethyl sulfoxide (DMSO), intraperitoneally (i.p.)) or APAP (80 mg/kg or 500 mg/kg in DMSO, i.p.; equivalent to a 900 mg or 5600 mg daily dose for a 70 kg human subject). BBB permeability was measured via in situ brain perfusion using [¹⁴C]sucrose and [³H]codeine, an opioid analgesic drug that is co-administered with APAP (i.e., Tylenol #3). Localization and protein expression of tight junction proteins (i.e., claudin-5, occludin, ZO-1) were studied in rat brain microvessels using Western blot analysis and confocal microscopy, respectively. Paracellular [¹⁴C]sucrose "leak" and brain [³H]codeine accumulation were significantly enhanced in rats treated with 500 mg/kg APAP only. Additionally, claudin-5 localization and protein expression were altered in brain microvessels isolated from rats administered 500 mg/kg APAP. Our novel and translational data show that BBB integrity is altered following a single high APAP dose, results that are relevant to patients abusing or misusing APAP and/or APAP/opioid combination products.

Acyclovir Brain Disposition: Interactions with P-gp, Bcrp, Mrp2, and Oat3 at the Blood-Brain Barrier

BACKGROUND AND OBJECTIVE

Acyclovir is effective in treating herpes simplex virus infections of the central nervous system. The purpose of this study was to investigate the interactions between acyclovir and the efflux pumps P-glycoprotein (P-gp), breast cancer resistance protein (Bcrp), multidrug resistance protein 2 (Mrp2), and organic anion transporter 3 (Oat3) at the blood-brain barrier (BBB).

METHODS

Acyclovir concentrations in the blood and brain were evaluated by microdialysis and high-performance liquid chromatography. Acyclovir pharmacokinetic parameters, including the area under the unbound blood concentration-time curve (AUCu,blood), the area under the unbound brain concentration-time curve (AUCu,brain), and the ratio of AUCu,brain to AUCu,blood (Kp.uu.brain), were evaluated in the presence and absence of elacridar (P-gp/Bcrp inhibitor, 7.5 mg/kg), tariquidar (P-gp/Bcrp inhibitor, 7.5 mg/kg), MK571 (Mrp2 inhibitor, 7.5 mg/kg), cyclosporine (P-gp/Bcrp/Mrp2 inhibitor, 25 mg/kg), and probenecid (Oat3 inhibitor, 50 mg/kg).

RESULTS

The average AUCu,blood, AUCu,brain, and Kp.uu.brain in rats who received acyclovir (25 mg/kg, intravenous) alone were 1377.7 min · μg/ml, 435.4 min · μg/ml, and 31.6%, respectively. Probenecid drastically increased the AUCu,blood of acyclovir 1.73-fold, whereas coadministration with elacridar, tariquidar, MK571, and cyclosporine did not alter the blood pharmacokinetic parameters of acyclovir. Elacridar, tariquidar, MK571, cyclosporine, and probenecid significantly increased the AUCu,brain of acyclovir 1.51-, 1.54-, 1.47-, 1.95-, and 2.34-fold, respectively. Additionally, the Kp.uu.brain of acyclovir markedly increased 1.48-, 1.63-, 1.39-, 1.90-, and 1.35-fold following elacridar, tariquidar, MK571, cyclosporine, and probenecid administration, respectively.

CONCLUSION

The present study demonstrated that P-gp, Bcrp, Mrp2, and Oat3 inhibition increased the penetration of acyclovir across the BBB, supporting the hypothesis that these efflux pumps restrict the distribution of acyclovir in the brain.

Sorafenib Modulates the LPS- and Aβ-Induced Neuroinflammatory Response in Cells, Wild-Type Mice, and 5xFAD Mice

Sorafenib is FDA-approved for the treatment of primary kidney or liver cancer, but its ability to inhibit many types of kinases suggests it may have potential for treating other diseases. Here, the effects of sorafenib on neuroinflammatory responses in vitro and in vivo and the underlying mechanisms were assessed. Sorafenib reduced the induction of mRNA levels of the proinflammatory cytokines COX-2 and IL-1β by LPS in BV2 microglial cells, but in primary astrocytes, only COX-2 mRNA levels were altered by sorafenib. Interestingly, sorafenib altered the LPS-mediated neuroinflammatory response in BV2 microglial cells by modulating AKT/P38-linked STAT3/NF-kB signaling pathways. In LPS-stimulated wild-type mice, sorafenib administration suppressed microglial/astroglial kinetics and morphological changes and COX-2 mRNA levels by decreasing AKT phosphorylation in the brain. In 5xFAD mice (an Alzheimer’s disease model), sorafenib treatment daily for 3 days significantly reduced astrogliosis but not microgliosis. Thus, sorafenib may have therapeutic potential for suppressing neuroinflammatory responses in the brain.