Improvement of tissue survival of skin flaps by 5 alpha-reductase inhibitors: possible involvement of nitric oxide and inducible nitric oxide synthase

Skin flap grafting is a popular approach for reconstruction of critical skin and underlying soft tissue injuries. In a previous study, we demonstrated the beneficial effects of two 5alpha-reductase inhibitors, azelaic acid and finasteride, on tissue survival in a rat model of skin flap grafting. In the current study, we investigated the involvement of nitric oxide and inducible nitric oxide synthase [iNOS] in graft survival mediated by these agents. A number of 42 male rats were randomly allocated into six groups: 1, normal saline topical application; 2, azelaic acid [100 mg/flap]; 3, finasteride [1 mg/flap]; 4, injection of L-N[G]-nitroarginine methyl ester [L-NAME] [i.p., 20 mg/kg]; 5, L-NAME [20 mg/kg, i.p.] + azelaic acid [100 mg/flap, topical]; 6, L-NAME [20 mg/kg, i.p.] + finasteride [1 mg/flap, topical]. Tissue survival, level of nitric oxide, and iNOS expression in groups were measured. Our data revealed that azelaic acid and finasteride significantly increased the expression of iNOS protein and nitric oxide [NO] levels in graft tissue [P < 0.05]. These increases in iNOS expression and NO level were associated with higher survival of the graft tissue. It appears that alterations of the NO metabolism are implicated in the azelaic acid- and finasteride-mediated survival of the skin flaps

Calorie shifting diet versus calorie restriction diet: a comparative clinical trial study

Finding new tolerable methods in weight loss has largely been an issue of interest for specialists. Present study compared a novel method of calorie shifting diet [CSD] with classic calorie restriction [CR] on weight loss in overweight and obese subjects. Seventy-four subjects [body mass index >/= 25; 37] were randomized to 4 weeks control diet, 6 weeks CSD or CR diets, and 4 weeks follow-up period. CSD consisted of three phases each lasts for 2 weeks, 11 days calorie restriction which included four meals every day, and 4 h fasting between meals follow with 3 days self-selecting diet. CR subjects receive determined low calorie diet. Anthropometric and metabolic measures were assessed at different time points in the study. Four weeks after treatment, significant weight, and fat loss started [6.02 and 5.15 kg] and continued for 1 month of follow-up [5.24 and 4.3 kg], which was correlated to the restricted energy intake [P < 0.05]. During three CSD phases, resting metabolic rate tended to remain unchanged. The decrease in plasma glucose, total cholesterol, and triacylglycerol were greater among subjects on the CSD diet [P < 0.05]. Feeling of hunger decreased and satisfaction increased among those on the CSD diet after 4 weeks [P < 0.05]. The CSD diet was associated with a greater improvement in some anthropometric measures, Adherence was better among CSD subjects. Longer and larger studies are required to determine the long-term safety and efficacy of CSD diet

Caffeine treatment prevented from weight regain after calorie shifting diet induced weight loss

Low calorie diets are always difficult for obese subjects to follow and lead to metabolic and behavioral adaptation. Therefore, we evaluated the effect of caffeine treatment with calorie shifting diet [CSD] on weight loss. Female subjects [n=60; BMI>25] completed 4-weeks control diet, 6-weeks CSD [3 repeated phases; each 2-weeks] and 4-weeks follow-up diet, with or without caffeine treatment [5 mg/Kg/day]. The first 11 days of each phase included calorie restriction with four meals every day and 4 hours intervals. Significant weight and fat loss were observed after 4-weeks of CSD [5.7 +/- 1.24 Kg and 4.84 +/- 1.53 Kg] or CSD+Caffeine [7.57 +/- 2.33 Kg and 5.24 +/- 2.07 Kg] which was consistent for one month of the follow-up [CSD: 5.24 +/- 1.83 Kg and 4.3 +/- 1.62 Kg, CSD+Caffeine: 12.11 +/- 2.31 Kg and 9.85 +/- 1.6 Kg, p < 0.05 vs CSD group] and correlated to the restricted energy intake [p < 0.05]. During three CSD phases. RMR tended to remain unchanged in both groups. While, CSD or CSD + Caffeine treatments, significantly decreased plasma glucose, total-cholesterol, and triacylglycerol [p < 0.05], even during follow-up period [p < 0.05]. HDL-cholesterol was not changed by CSD. Feeling of hunger decreased and subject's satisfaction increased after 4-weeks of CSD [p < 0.05] and remained low to the end of study, while satiety was not affected. Coffeine increased the effect of CSD on feeling of hunger and subject's satisfaction after week 7 [p < 0.05 vs. CSD]. These findings indicated that combination of caffeine treatment with CSD could be an effective alternative approach to weight and fat loss with small changes in RMR and improved tolerance of subjects to the new diet

Nitric oxide is necessary for diazoxide protection against ischemic injury in skeletal muscle

Ischemia reperfusion injury [IR injury] is a common problem in clinical conditions. Researches have frequently revealed that ATP- sensitive potassium [K[ATP]] channels and nitric oxide plays a role in protection against ischemic injury in skeletal muscle. The present study aimed at evaluating the possible link between this two pathways. Sixty-eight male wistar rats, were pretreated with saline, diazoxide [K[ATP] opener; 45 mg/Kg, IP], glibenclamide [K[ATP] inhibitor; 5 mg/Kg], or L-NAME [iNOS inhibitor; 20 mg/Kg, IP] before 3 h ischemia and 2 h reperfusion. Activities of antioxidant enzymes superoxide dismutase [SOD] and catalase [CAT], and the level of malondialdehyde [MDA] and expression of iNOS were measured in muscle tissue. Tissue MDA content was significantly increased by IR [p < 0.001]. Diazoxide significantly decreased the IR-induced elevation of tissue MDA level [p < 0.05] and Glibenclamide increased MDA [p < 0.05 vs. IR group]. L-NAME inhibited the effect of diazoxide on decreasing MDA [p < 0.01 vs., diazoxide+IR group] and IR decreased the activity of SOD and CAT [p < 0.01], while pretreatment with diazoxide increased activity of SOD and CAT [p < 0.01]. Glibenclamide decreased SOD and CAT activity after IR [p < 0.05]. L-NAME pretreatment in diazoxide-treated rats abolished the effect of diazoxide on increasing the activity of SOD and CAT [p < 0.05 vs. Diaz+IR]. Expression of iNOS was increased by IR [p < 0.01 vs. Sham group]. Diazoxide significantly decreased iNOS expression after IR [p < 0.05 vs. IR]. L-NAME significantly decreased iNOS expression after IR [p < 0.01] in diazoxide-treated rats [p < 0.01 vs. Diaz+IR]

Effect of short and long-term treatment with omega-3 fatty acids on scopolamine-induced amnesia

Two omega-3 fatty acids including docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA] are essential for the physiologic function of neuronal cell membrane. Normal function of neuronal cell membrane requires appropriate composition of fatty in its structure. Present study was designed to compare the effect of short-term and long-term pretreatment with omega-3 fatty acids on scopolamine-induced amnesia and possible involvement of apoptotic or oxidative pathways. Male Wistar rats were gavaged by omega-3 fatty acids [60 mg/Kg [DHA + EPA]] or saline for 2 weeks [short-term model] or 8 weeks [Long-term model], then received intra-CA1 scopolamine [2 mg/rat]. Finally, the avoidance response was examined and hippocampus tissue was prepared. Intra-CA1 injection of scopolamine abolished the memory performance in rats. Short-term or long-term pretreatment with omega-3 fatty acids improved memory [p < 0.01 and p < 0.001, respectively]. Pretreatment for 2 weeks had no effect on the tissue Malondialdehyde [MDA] contents or SOD and CAT activity. In addition, pretreatment for 2 weeks with omega-3 fatty acids had no effects on tissue Bax and Bcl-2 expression. Conversely, long-term pretreatment with omega-3 fatty acids decreased tissue MDA contents [p < 0.01], SOD activity [p < 0.05] and increased CAT activity [p < 0.01]. Long-term pretreatment with omega-3 fatty acids also decreased Bax protein expression [p < 0.05] with no effect on the expression of Bcl-2 protein. In conclusion, long-term exposure to omega-3 fatty acids inhibited the scopolamine-induced oxidative stress, apoptosis and amnesia while the effect of short-term treatment was restricted to the improved memory without significant effect on apoptosis or oxidative stress. Therefore, long-term treatment with low doses of omega-3 fatty acids suggested a suitable treatment for amnesia

BCL-2 and bax expression in skin flaps treated with finasteride or azelaic acid

Despite all modern surgical techniques, skin flap that is considered as the main method in most reconstructive surgeries puts the skin tissue at danger of necrosis and apoptosis derived from ischemia. Therefore, finding a treatment for decreasing the apoptosis derived from flap ischemia will be useful in clinic. In present study, we evaluated the effect of azelaic acid 20% and finasteride on expression of BCL-2 and bax proteins after the skin flap surgery. For this purpose, 21 rats were entered in three groups including control, azelaic acid 20% and finasteride, all experienced skin flap surgery and then flap tissue was assessed for determining the expression of proteins in 5 slices prepared from each rat that were graded between - to +++ scales. Both azelaic acid and finasteride increased the expression of BCL-2 protein [p < 0.05] and decrease the expression of bax protein [p < 0.05]. These results suggested an antiapoptotic role for finasteride and azelaic acid in preserving the flap after the ischemia reperfusion insult

[ protective effect of azelaic acid 5% and minoxidil 5% combination therapy in reducing skin flap necrosis of rats]

One important limitation of random pattern skin flap in plastic surgery is the necrosis of distant parts of the flap resulting from ischemia. This effect cause unwanted increase in the costs and hospitalization. Previously, large number of factors has been evaluated to decrease the flap necrosis. In present study we used two drugs. Main reason was their mechanism of action that seems to be similar to preconditioning pathways. Fifty-six male rats were divided into four groups. In two groups 5% minoxidil or 5% azelaic acid were applied topically to the flap area before flap elevation. In some rats of minoxidil treated group, a non selective ATP sensitive potassium channel [KATP] blocker, glibenclamide [0.3mg/kg] was injected i.p. to evaluate the role of this channel in action. In azelaic acid treated rats, some were selected for evaluation of the role of nitric oxide and therefore L-NAME [20 mg/kg], a non-selective iNOS inhibitor, was administered. Seven days after operation, the extent of flap necrosis was calculated. Topical minoxidil or azelaic acid significantly recused necrotic area of skin flap to 42% [P<0.05] and 34% [P<0.01], respectively. Combination of minoxidil and azelaic acid was the most effictive intervantion on reducing of necrotic area to 26%. Glibenclamide abolished protective effect of minoxidil [P<0.001] and L-NAME inhibited the effect of azelaic acid on skin flap survival [P<0.05]. Both L-NAME and glibenclamide completely inhibited the effect of combination topical therapy. Present study suggested the role of KATP channels on minoxidil pathway and NO on L-NAME pathway of preserving skin flap survival. It seems that there is an overlap between the two pathways; however precise mechanism remained to be determined

mechanism of preventive effect of captopril on renal ischemia reperfusion injury is independent of ATP dependent potassium channels

Renal ischemia reperfusion [IR] injury has been a major source of concern during the past decades and angiotensin converting enzyme [ACE] inhibitors have been successfully used to prevent this injury. There have been some controversial reports about the involvement of KATP channels in the mechanism of action of ACE inhibitors. In this study, we examined the effect of KATP channel blocker [Glibenclamide] on preventive effect of captopril on renal IR injury. Male sprauge-dawley rats were pretreated with glibenclamide [1, 5 and 25 mg/kg] and/or captopril [5 mg/kg]. They were anesthetized using ketamine [50 mg/kg] and xylazine [10 mg/kg]. The left flank was incised and the left renal artery was clamped for 30 minutes. After that, the kidney was reperfused for 2 hours and then the animal was killed. The Right and left kidneys were removed and evaluated for microscopic damage. Captopril reduced renal IR injury while glibenclamide by itself caused no change. Glibenclamide did not change the preventive effect of captopril. It seems that the preventive effect of captopril is not directly mediated by KATP channels and further attention should be paid to other receptor-mediated angiotensin II effects