Effects of Repetitive Ischemic Preconditioning on the Expression of Nitric Oxide Synthase in Tibialis Anterior and Soleus Muscles of the Rat / 체질인류학회지

Nitric oxide synthases (NOSs) that catalyzed the conversion of L-arginine to nitric oxide and L-citrulline play a role in ischemic-reperfusion injury. The purpose of this study was to observe the expression patterns of nNOS, iNOS and eNOS in the rat tibialis anterior and soleus muscles after multiple cyclic episodes of ischemic preconditioning (IP). Nine weeks old male SD rats were divided into control and IP groups. The IP group was further divided into 3 groups based on cycle of IP. For IP, left commom iliac artery was occluded 3, 6 and 10 times for 5 minutes ischemia followed by 5 minutes reperfusion using rodent vascular clamps. The animals were sacrificed at 0, 3, 6, 24 and 72 hours of reperfusion and the left tibialis anterior and soleus muscles were removed. The expression of nNOS, iNOS and eNOS were examined with immunohistochemical methods and Western blot analysis. IP increased the expression of nNOS, compared with the control. In the tibialis anterior muscle, the levels of nNOS in the 3IP and 6IP were higher than that in 10IP. IP increased the expression of iNOS, compared with the control, and the levels of iNOS in tibialis anterior muscle were higher than that in soleus muscle. The level of iNOS in the 10IP was higher than those in the 3IP and 6IP. IP increased the expression of eNOS, compared with the control, and the level of eNOS in soleus muscle were higher than that in tibialis anterior muscle. At 0 and 3 hours after reperfusion, the level of eNOS in 6IP and 10IP were higer than that in 3IP. In summary, these results suggest that the ischemic preconditioning increases the expression of nNOS, iNOS and eNOS, and 10 times of ischemic preconditioning may induce ischemic injury through upregulation of iNOS. And tibialis anterior muscle is more susceptabile to ischemic injury than soleus muscle.

Expression Pattern of Nitric Oxide Synthases in Rat Skeletal Muscle after Cyclic Episodes of Short Ischemia and Reperfusion / 체질인류학회지

The ischemic preconditioning was initially identified as a protective maneuver induced by brief periods of ischemia followed by reperfusion. Although ischemic preconditioning can reduce ischemic injury of heart, skeletal muscle and neuronal tissue, it's protective mechanism remains elusive. Recently, several investigations suggest the associations of nitric oxide with protection from ischemic injury. Nitric oxide synthesized by a member of nitric oxide synthase (NOS) family has been known to increase or decrease the ischemic injury. The purpose of this study was to observe the expression patterns of NOS 1, NOS 2 and NOS 3 in the rat skeletal muscle after cyclic episodes of short ischemia and reperfusion. Nine and thirty-five weeks-old male Sprague-Dawley rats were divided into control and cyclic short ischemia and reperfusion groups. The experimental group was further divided into 3 groups based on cycles of short ischemia and reperfusion. For cyclic short ischemia and reperfusion, left commom iliac artery was occluded 3, 6 and 10 times for 5 minutes ischemia followed by 5 minutes reperfusion using rodent vascular clamps. The animals were sacrificed at hours 0, 3, 6, 24 and 72 after reperfusion and the left rectus femoris muscles were removed. The expression profiles and distribution of NOS 1, NOS 2 and NOS 3 were examined with immunohistochemical staining. The results were as follows; In the cyclic of short ischemia and reperfusion groups, the mortality was increased with increasing of cyclic episodes at 72 hours after reperfusion, and aging. In the control group, NOS 1, NOS 2 and NOS 3 immunoreactivities showed no differenes with aging. In the 9 weeks-old rats, NOS 1 immunoreactivities were observed moderate at 24 hours after 6 times of short ischemia and reperfusion, and moderate and strong at 24 hours after 10 times of short ischemia and reperfusion. In the 35 weeks-old rats, NOS 1 immunoreactivities were observed trace or mild at 24 hours after 6 and 10 times of short ischemia and reperfusion. At 3 hours after 3 times of short ischemia and reperfusion, NOS 2 immunoreactivities were observed moderate or strong, and trace in the 9 and 35 weeks-old rats, respectively. At 3 hours after 10 times of short ischemia and reperfusion, NOS 3 immunoreactivities were observed mild or moderate, and trace or negative in the 9 and 35 weeks-old rats, respectively. In summary, the expression profile of NOS 1, NOS 2 and NOS 3 were observed differently with increasing episodes of short ischemia and reperfusion. The alteration was the most prominent in NOS 3 than in NOS 1 and NOS 2. These results suggest that the alteration of NOS 3 known to protect tissue against ischemic injury may be associated with increasing mortality after multiple episodes of short ischemia and reperfusion.