Vitamin C supplementation modulates crude oil contaminated water induced gravid uterine impaired contractile mechanism and foetal outcomes in Wistar rats.

OBJECTIVES: Crude oil is a common environmental contaminant that impacts the reproductive functions of women. Understanding the contractile mechanism of the gravid uterus and how it impacts fetal outcomes during crude oil-contaminated water (CCW) exposure is still evolving. This study investigates the effect of vitamin C supplementation during the ingestion of CCW from Bayelsa, Nigeria, on the contractile mechanism of the gravid uterus and fetal outcomes. METHODS: Fifteen nulliparous pregnant rats were randomly divided into 3 groups of 5 rats each and treated with normal saline (control), CCW (2.5 mL), and CCW + vitamin C (10 mg/kg bwt), respectively. Treatments were via oral gavage from gestation days 1-19. Gas chromatography-mass spectrometry of CCW, uterine oxidative biomarkers, and in vitro contractile activity of excised uterine tissue to acetylcholine, oxytocin, magnesium, and potassium were determined. Furthermore, uterine responses to acetylcholine after incubation with nifedipine, indomethacin, and N-nitro-L-arginine methyl ester were also recorded using the Ugo Basile data capsule acquisition system. Fetal weights, morphometric indices, and anogenital distance were also determined. RESULTS: Acetylcholine, oxytocin, magnesium, diclofenac, and indomethacin-mediated contractile mechanisms were significantly impaired with CCW exposure; however, vitamin C supplementation significantly attenuated the impaired uterine contractile activity. Maternal serum estrogen, weight, uterine superoxide dismutase, fetal weight, and anogenital distance were significantly reduced in the CCW group compared to the vitamin C supplemented group. CONCLUSIONS: Ingestion of CCW impaired the uterine contractile mechanism, fetal developmental indices, oxidative biomarkers, and estrogen. Vitamin C supplementation modulated these by elevating uterine antioxidant enzymes and reducing free radicals.

Preliminary Mechanistic Study on the Trachea Smooth Muscle Relaxant Activity of Aqueous Leaf Extract of Tridax Procumbens in Male Wistar Rats.

Objectives: Aqueous leaf extract of Tridax procumbens (ALETP) has potent relaxant activity. However, this relaxant activity in respiratory smooth muscle remains uninvestigated. This study investigates the effect of ALETP on the contractile activity of tracheal smooth muscle (TSM) in adult male Wistar rats. Methods: Twelve male Wistar rats divided into 2 groups and were treated with either 100 mg/kg of ALETP (ALETP treatment group) or vehicle (distilled water; control group) through oral gavage for 4 weeks. Dose responses of TSM from the 2 groups to acetylcholine (10-9 to 10-5 M), phenylephrine (10-9 to 10-5 M), and potassium chloride (KCl; 10-9 to 10-4 M) were determined cumulatively. Furthermore, cumulative dose responses to acetylcholine (10-9 to 10-5 M) after pre-incubation of TSM with atropine (10-5 M), L-NAME (10-4 M), indomethacin (10-4 M), and nifedipine (10-4 M), were determined. Results: Treatment with ALETP substantially inhibited TSM contraction stimulated by cumulative doses of acetylcholine, phenylephrine, and KCl. Furthermore, preincubation of TSM from the 2 groups in atropine significantly inhibited contractility in TSM. Incubation in L-NAME and indomethacin also significantly inhibited contractility in TSM of ALETP-treated rats compared to that of controls. Contractile activity of the TSM was also inhibited significantly with incubation in nifedipine in ALETP-treated rats. Conclusion: ALETP enhanced relaxant activity in rat TSM primarily by blocking the L-type calcium channel and promoting endothelial nitric oxide release. ALETP contains agents that may be useful in disorders of the respiratory tract.

Mechanisms of inhibitory activity of root extract of Carpolobia lutea G. Don on in vitro contractile responses of rabbit corpus carvernosum.

INTRODUCTION: Carpolobia lutea root extract (CLRE) has been reported to enhance penile erection. However, the mechanism involved is poorly understood. We investigated in vitro mechanisms of CLRE action on contractile activity of rabbit corpus cavernosum (CC). METHODS: Corpus cavernosum strips from four healthy male New Zealand rabbits (2.5-3.0kg) were mounted on an organ chamber and contracted with phenylephrine (PE) (10-9 to 10-5M) and Potassium Chloride (KCl) (10-50mM) before treatment with various concentrations of CLRE (0.1-1.2mg/ml). Interactions between CLRE and a Nitric Oxide Synthase (NOS) inhibitor (N-nitro-l-arginine methyl ester - l-NAME 10-4M); guanylyl cyclase inhibitors (Oxalodiazolo 4,3-a quinoxalin-1-one - ODQ 10µM, 20µM, 30µM), and (methylene blue 10-30µM); a cyclooxygenase inhibitor (10-4M indomethacin); potassium-channel inhibitors (100µM tetraethyl ammonium TEA), (100ηM apamin) and (glibenclamide 10µM and 20µM); and a calcium-channel inhibitor (-10-4M nifedipine) were investigated. RESULTS: Maximal contractions of KCl and PE contracted CC strips were significantly reduced in a concentration-dependent manner (40.8±3.6% and 38.6±4.0% from 64.6±2.9% and 98.1±4.2% respectively). Relaxant effect of CLRE was significantly reduced by ODQ (38.6±4.0% to 6.4±1.3% and 38.6±4.0% to 7.2±1.2%), nifedipine (38.6±4.0% to 21.1±2.7%) and glibenclamide (40.8±3.6% to 31.5±3.3%). However l-NAME, indomethacin, methylene blue, TEA and apamin did not inhibit relaxation by CLRE. CONCLUSION: Concentration-dependent relaxant effect of CLRE in rabbit CC involves the soluble guanylate cyclase/cyclase Guanosine Monophosphate system, and activation of ATP-dependent K+ channels.

Effects of aqueous leaf extract of Tridax procumbens on contractile activity of corpus cavernosum in N-nitro-l-arginine methyl ester-induced hypertensive male rats.

OBJECTIVE: This study investigated the effects of aqueous leaf extract of Tridax procumbens (ALETP) on contractile activity of corpus cavernosum in N-nitro-l-arginine methyl ester (l-NAME)-induced hypertensive male rats. METHODS: Twenty normal, adult male rats (130-150 g) were divided into four groups of five rats each. Group I (control) was given normal saline (0.6 mL/kg) and group II was given l-NAME (40 mg/kg) for 6 weeks. Groups III and IV also received l-NAME (40 mg/kg) for 6 weeks but were further co-treated with 100 and 200 mg/kg of ALETP, respectively, from week 4 to week 6. All treatments were given orally. Strips of corpus cavernosum from each of the four groups were exposed to increasing concentrations of acetylcholine (ACh) and sodium nitroprusside (SNP) (10-9-10-5mol/L) after contraction with phenylephrine (10-7 mol/L) to test for a dose-response effect. Response to potassium and calcium was also measured after cumulatively adding potassium and calcium (10-50 mmol/L) to potassium- and calcium-free organ chamber. Isometric contractions were recorded through an Ugo Basile data capsule acquisition system. RESULTS: Mean arterial blood pressure was significantly reduced in the ALETP co-treated group compared to the control and l-NAME-only groups (P < 0.05). Cavernosa strips from ALETP co-treated rats exhibited significant inhibition of contraction in response to phenylephrine, potassium chloride, and calcium chloride (P < 0.05). Relaxation in response to Ach and SNP was also significantly impaired in cavernosa strips from the l-NAME-only treated group (P < 0.05), while ALETP co-treated groups showed enhanced percentage relaxation. CONCLUSION: ALETP treatment of l-NAME-induced hypertensive rats promotes a relaxant effect on isolated cavernosa strips. ALETP shows potential in correcting erectile dysfunction in hypertension.

Comparative evaluation of the aphrodisiac efficacy of sildenafil and Carpolobia lutea root extract in male rabbits.

AIMS: In spite of the folkloric use of the root of Carpolobia lutea as a sexual stimulant in man, there has been limited scientific proof of its efficacy. This study compares the efficacy of methanol extract of C. lutea root (MECLR) and sildenafil on the sexual activity of male rabbits. METHODS: 20 adult male rabbits were grouped into four of five rabbits each. Groups 1-4 were treated orally for 28 days with 2 ml/kg 1% Tween-20 (vehicle), 40 mg/kg MECLR, 80 mg/kg MECLR, and 0.5 mg/kg sildenafil citrate (SC), respectively. Sexual activities of males from each group were assessed by cohabiting them with sexually receptive female at estrus on days 0, 1, 3, and 5 using digital camera mounted on mating arena. Serum testosterone and nitric oxide concentration of the corpora cavernosa homogenates were also determined. RESULTS: MECLR caused a dose-dependent significant increase in mount frequency, intromission frequency and ejaculatory latency (EL) while it reduced mount latency, intromission latency and post EL (similar to SC) when compared with the control. MECLR also caused significant increase in nitric oxide concentration in corpora cavernosa but no change in serum testosterone concentration. CONCLUSIONS: Results suggest that MECLR enhances male sexual activity possibly by augmenting nitric oxide concentration. This study thus provides a novel scientific rationale for the use of C. lutea in the management of penile erectile dysfunction and impaired libido.