title: N-acetylcysteine inhibits loss of diaphragm function in streptozotocin-treated rats.
abstract: We examined whether streptozotocin (STZ)-induced diabetic rats have an impairment in diaphragm contractility, and if so, whether N-acetylcysteine (NAC), a nonspecific antioxidant, prevents this impairment. First, diaphragm contractility, assessed by tension-frequency relationships and twitch kinetics in in vitro diaphragm strip preparations of Wistar rats, was obtained on Days 3 and 7 after administration of STZ of 30 or 60 mg/kg body weight, and compared with that of the control group. Second, NAC at 500 mg/kg body weight or vehicle solution was administered orally every day in rats treated with STZ at 60 mg/kg body weight, and diaphragm function on Day 7 after starting NAC treatment was compared between vehicle control and STZ-treated groups. We found that diaphragm function in STZ-treated rats, which had hyperglycemia, decreased in a dose- and time-dependent manner. NAC inhibited the decrease in diaphragm contractility in STZ-treated rats without reducing blood glucose. These findings suggest that the loss of diaphragm function in STZ-induced diabetic rats is not directly related to hyperglycemia. The data are consistent with secondary alterations of normal cytokine signaling or changes in the redox state of the cell, both of which could be affected by NAC treatment.
authors.affiliation: First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: W
authors.initials: W
authors.lastname: Hida
authors.forename: C
authors.initials: C
authors.lastname: Shindoh
authors.forename: J
authors.initials: J
authors.lastname: Satoh
authors.forename: M
authors.initials: M
authors.lastname: Sagara
authors.forename: Y
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: T
authors.initials: T
authors.lastname: Toyota
authors.forename: K
authors.initials: K
authors.lastname: Shirato
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D003964:Diaphragm / Q000187:drug effects* / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin / Q000037:antagonists & inhibitors*; D013997:Time Factors
chemical_list: D000975:Antioxidants; D013311:Streptozocin; D000111:Acetylcysteine