Guilingji Protects Against Spermatogenesis Dysfunction From Oxidative Stress via Regulation of MAPK and Apoptotic Signaling Pathways in Immp2l Mutant Mice

Abstract

Male infertility is a major health issue with an estimated prevalence of 4.2% of male infertility worldwide. Oxidative stress (OS) is one of the main causes of male infertility, which is characterized by excessive reactive oxygen species (ROS) or lack of antioxidants. Meanwhile, it is reported that oxidative stress plays an important role in the spermatogenic impairment in Inner mitochondrial membrane peptidase 2-like (Immp2l) mutant mice. In this study, we focused on the potential mechanism of Guilingji in protecting the spermatogenic functions in Immp2l mutant mice. The results revealed that Immp2l mutant mice exhibit impaired spermatogenesis and histology shows seminiferous tubules with reduced spermatogenic cells. After administration of Guilingji [150 mg/kg per day intragastric gavage], however, alleviated spermatogenesis impairment and reversed testis histopathological damage and reduced apoptosis. What’s more, western blotting and the levels of redox classic markers revealed that Guilingji can markedly reduce reactive oxygen species. Moreover, Guilingji treatment led to inhibition of the phosphorylation of mitogen-activated protein kinase (MAPK), regulated apoptosis in the cells. In summary, Guilingji can improve spermatogenesis in Immp2l mutant mice by regulating oxidation-antioxidant balance and MAPK pathway. Our data suggests that Guilingji may be a promising and effective antioxidant candidate for the treatment of male infertility.

Antioxidant Behavioural Phenotype in the Immp2l Gene Knock-Out Mouse

“…As mentioned earlier, at least 19 different articles have been published describing oxidative stress in the earlier truncated Immp2l Tg(Tyr)979Ove mouse developed by Lu et al [ 3 , 28 , 29 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ]. Furthermore, all 19 of these articles noted increased ROS in this single mouse line.…”

“…Due to reports of oxidative stress in an earlier truncated Immp2l Tg(Tyr)979Ove mouse model [ 3 , 28 , 29 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ], we investigated whether oxidative stress was evident in our new Immp2l KD −/− KO mouse and/or whether it had a role in their enhanced amphetamine-induced locomotion. Our Western blot analyses demonstrate that the Immp2l KD −/− KO mouse [ 53 ] is devoid of Immp2l peptidase activity with no evidence of processing of two of the known Immp2l substrates Cyc1 and Gpd2 ( Figure 1 ).…”

“…The molecular basis for the differences in oxidative stress effects between our new Immp2l KD −/− KO mouse model and the earlier truncated Immp2l Tg(Tyr)979Ove mouse is uncertain [ 3 , 28 , 29 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ]. It is possible that the different strains of mice used had sufficiently different genetic backgrounds to differentially regulate gene-gene interactions and oxidative stress (i.e., C57BL/6J versus FVB/N mouse strains).…”

“…An earlier truncated Immp2l mouse model ( Immp2l Tg(Tyr)979Ove ) first reported in 2008 by Lu et al [ 3 ] and which subsequently became the subject of at least 18 additional publications [ 3 , 28 , 29 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ] presented with increased ROS and numerous associated oxidative stress phenotypes. Furthermore, this earlier truncated Immp2l Tg(Tyr)979Ove mouse had a complex genotype ( Immp2l Tg(Tyr)979Ove ) inclusive of an intragenic deletion in Immp2l and expressed a largely intact yet truncated form of Immp2l that made it difficult to determine the precise origin of the increased levels of ROS and associated oxidative stress phenotypes [ 3 ].…”

“…In addition, the earlier truncated Immp2l Tg(Tyr)979Ove mouse was developed on a blind background strain of mice (FVB/N) that made it unsuitable for behavioural examination [ 3 ]. As our primary interest is the aetiology of ASD-relevant behaviours, we developed the new Immp2l KD −/− KO mouse strain on a C57BL/6J background [ 53 ] that we demonstrate is devoid of Immp2l peptidase activity yet exhibits none of the overt oxidative stress-related phenotypes reported for the earlier truncated Immp2l Tg(Tyr)979Ove mouse model [ 3 , 28 , 29 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ].…”