Effects of 4% paraformaldehyde and modified Davidson’s fluid on the morphology and immunohistochemistry of Xiang pig testes

Abstract

Modified Davidson's Fluid (mDF) is a good fixative for morphological and antigen preservation. However, recent studies have shown that 4% paraformaldehyde (PFA) can better preserve the actin structure in rodent testes. It remains controversial which of these fixatives is best for testicular tissue. This study investigated the effects of both mDF and 4% PFA on the morphology and antigen preservation of Xiang pig testes using hematoxylin-eosin (HE) staining and immunohistochemistry (IHC). The stronger testis penetration of mDF compared with that of 4% PFA was primarily manifested as testicular color change and decrease in tissue weight loss. Testes fixed with 4% PFA displayed a severe shrinkage of both the tubular and interstitial compartments and the seminiferous tubule area decreased by 12.02% compared with that in mDF-fixed tissues. In contrast, IHC results showed that 4% PFA fixation achieved better IHC-positive performance than mDF fixation for antigens specifically expressed in germ cells, Leydig cells and Sertoli cells. Due to this improved antigen preservation by 4% PFA fixation, the relative immunoreactions intensity significantly increased by 39.8%, 27.8%, and 76.4%, respectively, compared with that in mDF fixation. In summary, fixation of Xiang pig testes with mDF was suitable for HE staining, while fixation with 4% PFA was more suitable for IHC.

The protective effects of exogenous spermine on renal ischemia-reperfusion injury in rats

“…After standing at 4 ℃ for 2 hours, samples were centrifuged at 1,500 ×g for 10 minutes, and the supernatant was cryopreserved. The renal tissue was fixed with 4% paraformaldehyde for 24 hours, and the sections were embedded according to the conventional method (25).…”

Longitudinal Expression of Testicular TAS1R3 from Prepuberty to Sexual Maturity in Congjiang Xiang Pigs

“…Each of the right testes were removed and cut into 2 portions of 1 cm 3 (10 nm × 10 nm × 10 nm) in volume. According to our previous studies [17], one portion was fixed in modified Davidson's fluid (mDF) for hematoxylin and eosin (H&E) staining and the other portion was fixed in 4% paraformaldehyde (PFA) for IHC analysis. Additionally, 60 day mouse testis sections were donated by Prof. Fangxiong Shi's group (Nanjing Agricultural University, Nanjing, China).…”

“…The amplification efficiency of all primer pairs ranged from 90.1-102.0%, and the R 2 values were greater than 0.99 ( Figure S3). [17]. The fixed testes were trimmed, subjected to routine histologic processing, and paraffinembedded.…”

“…To examine the localization of T1R3, T1R1, gustducin α-3 chain (GNAT3) and PLCβ2 in testes from the Congjiang Xiang pigs at prepuberty (30 day), early puberty (60 day), late puberty (90 day), and sexual maturity (120 day), IHC analyses were performed with the streptavidin-biotin complex (SABC) method [21]. Testis samples were fixed in 4% PFA at 4 • C for 24 h and processed in a series of graded ethanol solutions [17]. Testicular sections were deparaffinized and hydrated via graded xylene and ethanol, followed by heat-induced antigen retrieval in 0.01 M citrate buffer (pH, 6.0; microwave oven, 100 • C, 5 min).…”

Sweet Taste Receptor T1R3 Expressed in Leydig Cells Is Closely Related to Homeostasis of the Steroid Hormone Metabolism Profile

“…Congjiang Xiang pig is a miniature indigenous pig breed known for its small size, early sexual maturity, gene homozygosity, and anatomical and physiological similarity with humans . In this study, T1R3 expression was activated and inhibited in Leydig cells isolated from the Congjiang Xiang pig using saccharin sodium and lactisole to reveal the role of T1R3 in testosterone synthesis.…”