role of aminoguanidine on functional recovery of rat reperfused sciatic nerve

Ischemia reperfusion plays a major role in the development of pathological alterations in many different neuropathies. In this study, we evaluated the role of aminoguanidme [AG] in the functional recovery of the rat re-perfused sciatic nerve based on the behavioral scores. Seventy two rats were divided into 12 groups [n = 6]. We used ischemic model by occluding the right common iliac and femoral arteries for 3 h with a silk suture 6-0 using the slipknot technique. Treatment groups [2, 4, 6, 8, 10 and 12] received 150 mg/kg of AG intraperitoneally 24 hrs after the induction of ischemia. After certain time intervals of reperfusion [48 hr, and 4, 7, 14, and 28 days], the function of the hind limb was assessed using behavioral scores based on gait, racing reflex, toe spread, pinch sensitivity, paw position, and grasp. Hind limb functional deficits developed in all reperfused groups, and maximal behavioral deficit occurred on day 7 of reperfusion. The comparison of the control and AG groups revealed a better time course in recovery and improvement of the behavioral score. In conclusion, our findings suggest that post-ischernic administration of AG exhibits a neuroprotective effect against ischemia-reperfusion injury of sciatic nerve. However, further investigations are required to delineate the detailed mechanisms underlying the protective effect of AG in sciatic nerve injury

Effects of insulin and ascorbic acid on inhibition of the apoptosis in hippocampus of STZ-lnduced diabetic rats

The aim of this study was to investigate effects of insulin and ascorbic acid on rate of Caspase - 3 activity and DNA Laddering in hippocampus of STZ-induced diabetic rats. Thirty male Wistar rats in five groups, 6 in each group: one control group [group C] and four diabetic groups [diabetic control [group D], treatment with insulin [group I], with ascorbic acid [group AA] and with insulin plus ascorbic acid [group I+AA]] were used in this study. Diabetes was induced by injection of 60 mg/kg STZ IP. After six weeks, rats in group I were treated with insulin [4-6 U/kg/day Sc.], rats in group AA treated with ascorbic acid [200 mg/kg/day, IP] and rats in group I+AA treated with equal dosage of both insulin and ascorbic acid for two weeks. Rats in group D were treated with saline and considered as the diabetic control group. Two weeks after treatment, animals were anesthetized and hippocampus was dissected from hemispheres. Caspase-3 activity was assessed by Fluorometry, and finally, DNA fragmentation due to apoptosis was determined by DNA laddering Assay. Caspase-3 activity in group D significantly increased compared to group C [6.7 fold], whereas it decreased after treatment with insulin, ascorbic acid or both [2.6, 4.2 and 5.1 fold, respectively]. DNA laddering was observed in group D, but not in three treated groups. Conclusions: From this survey it was concluded that treatment of STZ-induced diabetic rats with insulin and/or L-ascorbic acid could possibly inhibit apoptosis in hippocampal tissues using decrease of Caspase -3 activity and prevention of DNA Laddering

[ study of effects of insulin and ascorbic acid on Bcl-2 family expression in hippocampus of streptozotocin -induced diabetic rats]

Diabetes is a metabolic disorder that has been shown to adversely affect both the central and peripheral nervous system by increasing basal neuronal apoptosis. Since Bcl-2 protein family is considered to play a key role in the regulation of apoptosis, in the present study we have examined the effects of insulin and ascorbic acid on expression of Bcl-2 family members including Bax [pro-apoptotic] and Bcl-2 and Bcl-x[L] [anti-apoptotic] on hippocampus of STZ-induced diabetic rats. Five groups of six Wistar rats including one control group [C] and four diabetic groups [D, I, AA and I+AA] were used in this study. Diabetes was induced by injection of 60 mg/kg STZ [IP]. After six weeks, rats in group I were treated with insulin [4-6 U/kg/day Sc], rats in group AA were treated with ascorbic acid [200 mg/kg/day IP] and rats in group I+AA were treated with equal dosage of both insulin and ascorbic acid for two weeks. Rats in group D were treated with normal saline and considered as diabetic control group. Two weeks after treatment, expression of Bcl-2, Bcl-x[L] and Bax genes were measured at both mRNA and protein levels. In diabetic control rats [group D], Bax increased whereas Bcl-2 and Bcl-x[L] decreased at both mRNA and protein levels compared to group C [P<0.01, P<0.001 respectively]. Interestingly, treatment with insulin [group I], ascorbic acid [group AA] and insulin plus ascorbic acid [group I+AA] could reverse these changes both at mRNA and protein levels [p<0.001 for I and AA+I groups, p<0.05 [Bcl-2] and p<0.01 [Bcl-x[L]] for AA group]. It is concluded that insulin and ascorbic acid alone or together can inhibit apoptosis in STZ-induced diabetic rats' hippocampus through increasing the ratio of Bcl-2/Bax and Bcl-x[L]/Bax expressions. We suggest that inhibition of apoptosis may prevent cognitive dysfunctions induced by hippocampal damage in diabetic patients as well. In addition, further experimental studies will need to be performed to confirm such effects

[ rare variation of sciatic nerve]

Sciatic nerve, as the largest branch of the sacral plexus and the thickest nerve of the body, forms from the union of ventral branches of L[4]-S[3]. Then it leaves the pelvis via the greater sciatic foramen below the piriformis and descends between the greater trochanter and ischial tuberosity. Afterwards, it divides into the tibial and the common proneal nerves, most frequently at the level of the upper angle of the popliteal fossa. Bifurcation into its two major divisions may occur, anywhere, between the sacral plexus and the upper angle of the popliteal fossa. However, concurrent occurrence of these variations: dividing of the sciatic nerve into two terminal branches in pelvis, existence of piriformis with completely separated upper and lower parts, the common proneal nerve passing through the two parts of piriformis in which one part of inferior gluteal nerve fibers and tibial nerve passing under the lower part of this muscle in company with the other part of inferior gluteal nerve, is a rare and very important phenomenon. This phenomenon may be of great importance in view of both entrapment of these members between two parts of piriformis which can lead to "piriformis syndrome", and being next to the muscular injection site of the gluteal region. Furthermore, it might be of major significance for medical specialists in particular for anatomists and surgeons to reduce the postoperative complications