[ effect of intra-cerebroventricular injection of insulin on nociception of formalin test in non-diabetic and short-term diabetic rat models]

Pain is a complex process in the central nervous system [CNS]. Several factors can alter the pain threshold and insulin is one of them which is produced by the beta cells of pancreas and capable of crossing blood-brain barrier. The aim of this study was to evaluate the effects of intra-cerebroventricular [ICV] injection of insulin on the pain response to formalin in short-term induced diabetic and non-diabetic rats. Sixty-four Sprague-Dawley male rats [280 +/- 30 g] were divided into non-diabetic and diabetic groups. Diabetes was induced with streptozotocin [STZ, 60 mg/kg, i.p] for elimination of peripheral insulin. After proving diabetes, insulin [5 mU/animal, 5 microL] was injected to the left lateral cerebral ventricle while equal volume of normal saline was injected in control groups. After 10 min, formalin test was performed. Present study showed that ICV injection of insulin possessed anti-nociceptive effect in non-diabetic rats in formalin test while in diabetic rats, it did not have this effect and even decreased pain threshold partially. In conclusion we showed that ICV injection of insulin in non-diabetic rats, in contrast with diabetic rats, has an anti-nociceptive effect in formalin test. In short-term diabetic rats, ICV injection of insulin was not able to reduce pain response and partially decreased pain threshold

[The effects of probiotic, prebiotic and synbiotic diets containing Bacillus coagulans and inulin on rat intestinal microbiota]

An in vivo experiment was conducted to study the effects of probiotic Bacillus coagulans spores, with and without prebiotic, inulin, on gastrointestinal [GI] microbiota of healthy rats and its potentiality to survive in the GI tract. Forty-eight male Wistar rats were randomly divided into four groups [n=12] and fed as follows: standard diet [control], standard diet supplied with 5% w/w long chain inulin [prebiotic], standard diet with 109/day spores of B. coagulans by orogastric gavage [probiotic], and standard diet with 5% w/w long chain inulin and 109 spores/day of B. coagulans by orogastric gavage [synbiotic]. Rats were fed the diets for 30 days. At day 10, 20 and 30 of experiment, 24 h post administration, four rats from each group were randomly selected and after faecal collection were sacrificed. Small intestine, cecum, and colon were excised from each rat and used for microbial analysis. Administration of synbiotic and probiotic diets led to a significant [P<0.05] increment in lactic acid bacteria [LAB], total aerobic and total anaerobic population compared the prebiotic and control diets. A significant decrease in Enterobacteriaceae counts of various segments of GI tract [except small intestine] in synbiotic, probiotic and prebiotic fed groups were also seen. The obvious decline in spores count through passing GI tract and high surviving spore counts in faecal samples showed that spores are not a normal resident of GI microbiota and affect intestinal microbiota by temporary proliferation. In conclusion, the present study clearly showed probiotic B. coagulans was efficient in beneficially modulating GI microbiota and considering transitional characteristics of B. coagulans, daily consumption of probiotic products is necessary for any long-term effect.

Effect of adding inulin on microbial and physico-chemical properties of low fat probiotic yogurt

Currently, due to their beneficial effects, there is interest in adding prebiotics to food products. This study investigated the effect of the addition of inulin [1% and 2%] on microbial and physico-chemical properties of probiotic low fat yogurt manufactured with Lactobacillus acidophilus. Six experimental preparations of yogurt were produced. Homogenized, standardized and pasteurized low fat milk were divided into six portions. Four portions were fortified with 1% and 2% inulin and two portions were used without inulin. All of the preparations were heated up to 85 [degree sign] C and fermented at 43 [degree sign] C until a pH of 4.6 was reached. Titratable acidity and pH were determined using the incubation period of the samples and a storage time up to 14 days. Syneresis, color, sensory evaluation and bacterial counts were determined during the storage time. The results showed that inulin did not significantly affect the titratable acidity and pH of the yogurts after 4 h of fermentation at 40 [degree sign] C. There were no significant differences between pH, titratable acidity, syneresis, color and sensory evaluation of all treatments on days 1, 7 and 14 of storage. The counts of L. acidophilus and L. delbrueckii ssp. bulgaricus declined over time, but the addition of inulin to the milk increased the viability of these bacteria during the storage of symbiotic yogurt. In conclusion, inulin can be used to manufacture low fat symbiotic yogurt with additional nutritional benefits without affecting the physic-chemical properties of yogurt