Effect of zidovudine an anti-human immune deficiency virus [HIV] on skeletal and cardiac muscles of adult albino rat. evaluation of the possible role of some antioxidants

ABSTRACT

Antiretroviral agents are the cornerstone in the management of Human Immunodeficiency Virus [HIV]. Zidovudine, a potent inhibitor of retroviral replication was the first drug approved for the treatment of Acquired Immunodeficiency Syndrome [AIDS]. Long term use of zidovudine in patients with AIDS is frequently associated with periods of dose reduction or discontinuation of therapy due to the development of muscular toxicity. Zidovudine toxicity is thought to be mediated through its action on mitochondria with increased reactive species and oxidative DNA damage. Some antioxidants [vitamin C, zinc and N-acetyl cysteine] were tried in this work aiming to evaluate their possible protective effects on zidovudine-induced muscle toxicity. Forty eight adult albino rats of both sexes were used in this study divided equally into the following groups group I was considered as a control group. Group II in which animals received vitamin C orally at a dose of 175mg/day. Group III included animals which received zinc oxide orally at a dose of 6 mg/day. Group IV in which animals received N-acetyl cysteine [NAC] orally at a dose of 18 mg/day. The drugs used in groups II, III and IV were given for 50 consecutive days. Group V included animals which received zidovudine [AZT] in a therapeutic dose [10.8 mg/rat] orally for 35 consecutive days. Group VI comprised animals which were pretreated with vitamin C for 15 days then vitamin C was given concomitantly with AZT for 35 consecutive days at the same previously given dose and route for each. Group VII in which animals were pretreated with zinc oxide for 15 days then zinc oxide was given concomitantly with AZT for 35 consecutive days at the same previously given dose and route for each. Group VIII comprised animals which received NAC for 15 consecutive days then it was given concomitantly with AZT for 35 consecutive days at the same previously given dose and route for each. At the end of the experiment blood samples were collected for detection of serum malondialdehyde [MDA] level, animals were sacrificed and the heart and gastrocnemius muscle were prepared for histological examination. In AZT group the L/M examination of skeletal and cardiac muscle sections revealed focal areas of necrosis with complete loss of architecture together with mononuclear cellular infiltration. Skeletal muscles of the same group showed focal depletion of sarcoplasmic PAS positive material and mitochondrial content and increase in collagen fiber deposition. E/M examination of cardiac myocytes showed abundant sarcoplasmic vacuolation and myofibrillar loss. Their mitochondria showed different grades of degenerative changes in the form of disrupted cristae, focal areas of matrical loss and ruptured membrane. Marked elevation of the level of serum malondialdehyde [MDA] was also detected. Nearly complete normalization of the histological profile of the skeletal and cardiac muscle was obtained in AZT and vitamin C group [VI] and AZT and zinc group [VII] as well as marked drop in the level of serum [MDA]. Meanwhile, mild improvement of the skeletal and cardiac muscle AZT-induced histological and biochemical changes was detected in AZT and NAC group [VIII]