Changes in lectin binding in rat testis and epididymis in association with experimental cryptorchidism, in which adult male Wistar rats were subjected to unilateral cryptorchid surgery, were examined by light and electron microscopy with 9 biotinylated-lectins (ConA, WGA, RCA, SBA, DBA, PNA, UEA-I, GS-I and GS-II). In the control testis, ConA, WGA, RCA and GS-I intensely stained every stage of germ cells. PNA, SBA and GS-II bound to all germ cells except spermatogonia. DBA and UEA-I reactions were identified only in spermatocytes and spermatids. Electron microscopically, reaction products were observed mainly along the plasma membrane and in the Golgi apparatus of each germ cell. In addition, the acrosome and/or acrosomal cap were strongly stained with PNA, SBA, WGA, and RCA. In the epididymis, lectin stainings were positive as follows: ConA, WGA, RCA and UEA-I; in all segments examined; PNA; in segments I and II; SBA, DBA, and GS-II; mainly in segments I, II, and V; GS-I; in segments II, III, and V. Electron microscopically, lectin binding sites were distributed mostly on the apical plasma membrane, microvilli, Golgi apparatus, and granules of the principal cells. Two weeks after the cryptorchid operation, stainings of all the lectins used were decreased in intensity and sometimes negative in the spermatogenic cells of the testis. In the epididymis, lectin staining was decreased primarily in segments I, II, and V. The present results indicate that certain glycoconjugates containing Gal, GaINAc, and GIcNAc residues are expressed in the acrosome. In cryptorchidism, the elevated environmental temperature caused the decrease in lectin stainings in testis, reflecting temperature-sensitive changes in cell-associated glycoconjugates during spermatogenesis. The decrease in lectin staining of segments I, II, and V in the epididymis under cryptorchid condition suggests that these segments may play a role for maturation of spermatozoa and that glycoconjugates in these segments are easily affected by an elevated environmental temperature.
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