A Toxic Cardiomyopathy Caused byCassia occidentalis. II. Biochemical Studies in Poisoned Rabbits

Abstract

Abstract. Mitochondrial damage was evident in the earliest lesions in cardiac muscle of rabbits poisoned by coffee senna (Cassia occidentalis), suggesting that mitochondria might be the target for the toxic action of coffee senna. Oxidative phosphorylation by mitochondria isolated from poisoned rabbits was uncoupled, and in more severely affected rabbits mitochondrial respiration was depressed. The activities of myocardial malic dehydrogenase, isocitric dehydrogenase and lactic dehydrogenase were increased, glycogen was depleted, and lactate accumulated in poisoned rabbits. The toxin(s) of coffee senna induced uncoupling of oxidative phosphorylation in myocardial mitochondria. Thus, the mitochondria, deprived of their ability to convert the energy derived from respiration into adenosine triphosphate, were unable to maintain ionic gradients and became swollen. This caused progressive failure of respiration with subsequent disruption of myocardial mitochondrial structure and myocardial degeneration.The morphologic characteristics of the cardiomyopathy of rabbits poisoned by coffee senna (Cassia occidentalis) have been described [27]. This and other studies [29] indicated that mitochondrial degeneration was an early lesion of coffee senna poisoning of rabbits and cattle that preceded myofibriIIar degeneration and also that mitochondria might be the target of the toxin(s) of coffee senna.Biochemical studies of animals poisoned by coffee senna have been limited to demonstration of increased activities of glutamic-oxalacetic transaminase (GOT), creatine phosphokinase (CPK) and isocitric dehydrogenase (I CD) in serum, hyperkalemia and myoglobinuria [23,27]. These changes are consistent with acute myodegenerative disease but do not reveal the pathogenesis of the muscle degeneration. In view of the morphological evidence of mitochondrial damage, the function of mitochondria isolated from the hearts of rabbits poisoned by coffee senna was studied using polarographic techniques to evaluate the status of mitochondrial respiration [5,20]. These techniques have been used by others in the study of various cardio-

Mitochondrial Myopathy inSenna occidentalis-Seed-Fed Chicken

“…O'Hara and Pierce found (O'Hara and Pierce, 1974a) that seeds of C. occidentalis induced uncoupling of oxidative phosphorylation and depressed respiration in mitochondria isolated from the heart of poisoned rabbits. Other biochemical studies of mitochondrial particles of chicken liver demonstrated lower phosphorylation ratios, and lower rates of oxygen use (Graziano et al, 1983).…”

Hepatoencephalopathy syndrome due to Cassia occidentalis (Leguminosae, Caesalpinioideae) seed ingestion in horses

“…The exact Cassia seed toxins in natural or experimental cases are unknown [1,5,13,15,16,18,21,23,24]. Alkaloids and triterpens have been found in liver and muscle samples from cattle poisoned by C. occidentalis seeds [8].…”

“…Clinical cases have been anecdotally mentioned in horses but frequently lack a detailed description [14]. Experimental intoxication has been demonstrated in cattle [13,18], goats [3,19], chickens [4,5,20,21], rats [1,22], rabbits [12,23,24] and horses [25,26]. Experimentally poisoned horses are severely ataxic and may die acutely without showing any clinical signs.…”