Changes in antioxidant enzymes and lipid peroxidation in extensor digitorum longus muscles of streptozotocin-diabetic rats may contribute to muscle atrophy

Abstract

We investigated muscle atrophy, major antioxidant enzymes and lipid peroxidation in the extensor digitorum longus (EDL, predominantly fast fibers) and soleus (predominantly slow fibers) muscle of streptozotocin-diabetic rats. Female Wistar rats were divided into a control (n = 5) and streptozotocin-induced diabetic group (n = 5). Eight weeks after diabetes induction the EDL and soleus muscles were removed and catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase activity (SOD), and thiobarbituric acid reactive substances (TBARS) levels measured. The CAT activity increased in both the EDL and soleus muscles of the diabetic rats (p < 0.01), whereas the GPX and SOD activities were increased only in the EDL muscle (p < 0.01 and p < 0.05). The TBARS levels were only increased in the EDL muscle of the diabetic rats (p < 0.01). Both muscles showed significant atrophy but the EDL muscle elicited the greatest atrophy. In conclusion, it appears that adaptive responses to oxidative stress were adequate in the soleus muscle, but not in the EDL muscle, of diabetic rats. Thus fast twitch muscle fibers may be more susceptible to oxidative stress than slow twitch muscle fibers and this may contribute to muscle atrophy under diabetic conditions.

Heat stress attenuates skeletal muscle atrophy of extensor digitorum longus in streptozotocin-induced diabetic rats

“…In contrast, muscle weight was decreased in both the DM and DM + HS groups. Moreover, the body weight of rats in the DM and DM + HS groups decreased; these results are consistent with the findings of previous studies on STZinduced diabetic rats (1,11). It is well known that muscle weight is influenced by body weight.…”

“…In our previous study, we demonstrated that oxidative stress is increased in the EDL muscles of STZ-induced diabetic rats (11). Heat stress provides protection against oxidative stress and preserves muscle mass during hind limb immobilization (17).…”

“…These findings suggest that overall stress was greater in diabetic rats than in non-diabetic rats when heat stress was applied. Diabetes is known to increase oxidative stress in skeletal muscle (11); hence, diabetic rats may have suffered greater oxidative stress in addition to the applied heat stress, and consequently their overall stress was increased relative to that of non-diabetic rats. This may explain the higher levels of HSPs observed in the DM + HS group compared with the HS group.…”

“…The rats were randomly divided into four groups with six animals per group: control (Con), heat stress (HS), STZ-induced diabetic (DM), and STZ-induced diabetic/heat stress (DM + HS). Diabetes was induced, according to methods described in a previous study (11), by a single intraperitoneal injection of STZ (50 mg/kg body weight; Wako Pure Chemical Industries, Ltd., Osaka, Japan) dissolved in physiological saline. Equivalent amounts of the vehicle were injected into rats of the non-diabetic groups.…”

Heat Stress Prevents the Decrease in Succinate Dehydrogenase Activity in the Extensor Digitorum Longus of Streptozotocin-Induced Diabetic Rats

“…The rats were randomly divided into four groups consisting of six animals per group as follows: control (Con), HS, diabetes mellitus (DM), and diabetes mellitus and heat stress (DM+HS). Diabetes was induced by a single intraperitoneal injection of STZ (50 mg/kg body weight; Wako Pure Chemical Industries, Ltd., Osaka, Japan) dissolved in physiological saline according to a previous study (Nonaka et al 2014).…”