Isoflurane as an anesthetic for experimental animal surgery

Isoflurane is an inhalational anesthetic agent associated with no known hepatic toxicity. Despite this fact, isoflurane has not been widely utilized as an anesthetic agent in studies of liver structure and function in experimental animals. For this reason, livers from rats treated with pentobarbital or diethylether were compared to those from rats treated with isoflurane to determine differences in biochemical and morphologic parameters. Liver from pentobarbital-treated rats showed a significant decline in glutathione-S-transferase activity compared to liver from isoflurane/O2 or ether-treated rats. Liver microsomes from isoflurane/O2-treated rats retained more cytochrome-C(P450)-reductase activity than did those from pentobarbital-treated, ether-treated, or decapitated rats. Despite these biochemical alterations, morphometric analysis of liver from isoflurane/O2 and pentobarbital-treated rats showed no quantitative or qualitative differences in liver structure or organelle volume densities. Neither were differences detected in uptake and distribution of 125I-epidermal growth factor when analyzed by electron microscopic autoradiography. These data show that isoflurane with supplemental O2 has no effects on hepatic structure and fewer effects on hepatic function than other anesthetics and may be a better experimental anesthetic than any currently in use.