Effects of Salmon Calcitonin and Omega - 3 Fatty Acids on Glucoregulatory Indices, Lipid Profile and Antioxidant Markers in Experimental Knee Osteoarthritis in Wistar Rats.

It has been opined that a combined therapeutic approach should be considered in the optimal management ofosteoarthritis (OA). Therefore, the study investigated the effects of salmon calcitonin (Sct) and/or omega-3 fatty acids (N-3), relative to diclofenac sodium (DF) on selected biochemical parameters in induced osteoarthritic rats. Forty (40) adultmale Wistar rats were used for this study. The rats were divided into 8 groups (n=5), viz: Group 1-Normal control; Group 2-OA control; Group 3-OA+N-3 (200 mg/kg, p.o.); Group 4-OA + low dose of Sct (Sct.Lw-2.5 IU/kg, i.m.); Group 5-OA +high dose of SCT (Sct.Hi-5.0 IU/kg, i.m.); Group 6-OA+N-3+Sct.Lw; Group 7-OA+N-3+Sct.Hi; and, Group 8-OA+DF (1mg/kg, p.o.). Osteoarthritis was induced with 4 mg of sodium monoiodoacetate in 40 µl of saline. The solution was injectedintra-articularly into the left knee joint space of anaesthetised (sodium pentobarbital - 40 mg/kg, i.p.) rats. Nine (9) daysafterwards, treatments started, and they lasted for 28 days. The results showed that Sct has hypocalcaemic, hypocortisolism,and anti-dyslipidaemic effects. It significantly inhibited nitric oxide (NO) production and insulin release. Like Sct, N-3 havehypocortisolism and anti-dyslipidaemic actions. Nevertheless, they caused significant increases in hepatic glycogen contentand plasma levels of calcium ion, insulin and NO. Although DF was also observed to stimulate insulin release and NOsynthesis, it significantly increased plasma level of LDL-c, but significantly decreased HDL-C. In conclusion, N-3 annul theundesirable effect of Sct, presenting it as a better anti-arthritic drug. Moreover, the combined administration of bothpharmacological agents proffer preferable therapeutic benefits in OA condition relative the single or DF therapy.

Vitamin C Prevents Sleep Deprivation-induced Elevation in Cortisol and Lipid Peroxidation in the Rat Plasma.

Sleep deprivation (SD) is biological stressor that alters metabolic parameters, induced oxidative stress and lipid peroxidation. Previous studies have shown that antioxidants substances such as melatonin, tryptophan, vitamin E and vitamin C improved stress tolerance in laboratory animals. In this study, we examined the potential protective effects of administration of vitamin C on acute and chronic sleep deprivation-induced metabolic derangement. In addition, possible processes involved in vitamin C effects on acute and chronic sleep deprivation-induced metabolic derangement were determined. Thirty-five rats (120-250g) were used. The rats were divided into 7 groups of 5 rats each as Control (CTRL), Acute sleep deprived untreated with vitamin C (AC), Acute sleep deprived treated with vitamin C (AWC), Chronic sleep deprived untreated with vitamin C (CC), Chronic sleep deprived treated with vitamin C (CWC), Chronic sleep deprived + Recovery untreated with vitamin C (RC), and Chronic sleep deprived + Recovery treated with vitamin C (RWC). The SD was carried out for 20h for 1 day on the acute groups, and for 20h/day for 5 days on the chronic group, using the Multiple Modified Platforms (MMP) after oral administration of 300mg/kg of vitamin C to all vitamin C-treated groups. The recovery groups were further observed for five days after SD. The control group were treated with vitamin C and without stress in their home cages. At the end of the experiment, the animals were sacrificed and blood was collected for estimation of plasma glucose, insulin, cortisol and malondialdehyde (MDA). The results showed that acute and chronic SDs significantly  increased MDA and cortisol levels, while significantly reduced the levels of insulin. Treatment with vitamin C reversed the changes in the MDA, cortisol and plasma insulin levels. Additionally, allowing the rats to recover for 5 days after sleep deprivation corrected the observed changes. Plasma glucose was significantly reduced in all the sleep deprived groups compared to the control. In conclusion, sleep deprivation induced metabolic, hormonal and lipid peroxidation derangement, and treatment with vitamin C prevented these impairments. Thus, the effects of vitamin C could improve stress tolerance in rats.

Effect of photoperiod on testicular functions in male Sprague-Dawley rats.

Variation in reproductive status in response to photoperiods has been observed in laboratory rats. We investigated the effects of photoperiod on testicular activity in Sprague-Dawley rats (Rattus norvigicus) maintained in experimental photoperiodic condition. Twenty-four adult male rats weighing 170+/-10g were conditioned to different lighting conditions of Light/Dark (LD) Cycle for 6 weeks. Group 1, Control group (LD12:12, light on from 07:00hr to 19:00hr). Group 2, Short Photoperiod group (LD 8:16hr, light on from 09:00hr to 17:00hr). Group 3, Long Photoperiod group (LD 16:8hr, light on from 05:00hr to 21:00hr). A significant influence of different lighting conditions on the testicular parameters was observed. Short photoperiod showed a suppressing effect (P < 0.001) on testicular weight, sperm motility sperm viability and sperm counts, while long photoperiod had an inducing, though insignificant, effect on the measured parameters. The results confirmed that Sprague-Dawley rats are photoresponsive and changes in the photoperiod could influence their reproductive functions.